diff --git a/set-definitions/src/main/java/eu/europeana/set/definitions/model/utils/UserSetUtils.java b/set-definitions/src/main/java/eu/europeana/set/definitions/model/utils/UserSetUtils.java
index b2831a12..4d981cef 100644
--- a/set-definitions/src/main/java/eu/europeana/set/definitions/model/utils/UserSetUtils.java
+++ b/set-definitions/src/main/java/eu/europeana/set/definitions/model/utils/UserSetUtils.java
@@ -167,5 +167,18 @@ public static String extractItemIdentifier(String dataEuropeanaUri,  String item
       return StringUtils.substring(dataEuropeanaUri, itemDataEndpoint.length());
     }
     }
+
+    //returns -1 if invalid or not provided
+    public static int parseItemsPosition(String position) {
+      int positionFinal = -1;
+      if (StringUtils.isNotEmpty(position)) {
+        try {
+          positionFinal = Integer.parseInt(position);
+        } catch (RuntimeException e) {
+          return -1;
+        }
+      }
+      return positionFinal;
+    }
  
 }
diff --git a/set-integration-testing/src/integration-test/java/eu/europeana/api/set/integration/web/EntityBestItemsSetIT.java b/set-integration-testing/src/integration-test/java/eu/europeana/api/set/integration/web/EntityBestItemsSetIT.java
index 51585cb9..11601192 100644
--- a/set-integration-testing/src/integration-test/java/eu/europeana/api/set/integration/web/EntityBestItemsSetIT.java
+++ b/set-integration-testing/src/integration-test/java/eu/europeana/api/set/integration/web/EntityBestItemsSetIT.java
@@ -8,7 +8,10 @@
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+import java.util.ArrayList;
+import java.util.List;
 import org.apache.commons.lang3.StringUtils;
+import org.codehaus.jettison.json.JSONArray;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -453,6 +456,97 @@ void insertPinnedItems_EntityUserSets_withEditorUser() throws Exception {
     // getUserSetService().deleteUserSet(identifier);
   }
 
+  // test insert multiple items
+  @Test
+  void insertMultipleItems_EntityUserSets_withEditorUser() throws Exception {
+    WebUserSetImpl userSet = createTestUserSet(ENTITY_USER_SET_REGULAR, editorUserToken);
+    String identifier = userSet.getIdentifier();
+
+    List<String> newItems=new ArrayList<>();
+    String item1="http://data.europeana.eu/item/01/123_pinnedItem";
+    String item2="/02/123_pinnedItem";
+    JSONArray newItemsJson = new JSONArray();
+    newItemsJson.put(item1);
+    newItemsJson.put(item2);
+
+    String result = mockMvc
+        .perform(
+            put(BASE_URL + "{identifier}/items", identifier)
+                .content(newItemsJson.toString())
+                .queryParam(WebUserSetFields.PATH_PARAM_POSITION,
+                    WebUserSetModelFields.PINNED_POSITION)
+                .header(HttpHeaders.AUTHORIZATION, editor2UserToken)
+                .header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE))
+        .andExpect(status().is(HttpStatus.OK.value()))
+        .andReturn().getResponse()
+        .getContentAsString();
+
+    assertTrue(containsKeyOrValue(result, userSet.getId()));
+
+    UserSet existingUserSet = getUserSetService().getUserSetById(userSet.getIdentifier());
+    //check for the new items
+    assertEquals(0, existingUserSet.getItems().indexOf(item1));
+    assertEquals(1, existingUserSet.getItems().indexOf(item2));
+    assertEquals(2, existingUserSet.getPinned());
+    assertEquals(4, existingUserSet.getItems().size());
+
+    // insert pinned items, some of which already exist (and can be pinned or not-pinned in the set)
+    newItems.clear();
+    String item3="/03/123_pinnedItem";
+    newItems.add(item2);
+    String item4Existing=existingUserSet.getItems().get(2);
+    newItems.add(item4Existing);
+    newItems.add(item3);
+    getUserSetService().insertMultipleItems(newItems, WebUserSetModelFields.PINNED_POSITION, -1, existingUserSet);
+    //check the new items
+    assertEquals(0, existingUserSet.getItems().indexOf(item2));
+    assertEquals(1, existingUserSet.getItems().indexOf(item4Existing));
+    assertEquals(2, existingUserSet.getItems().indexOf(item3));
+    assertEquals(3, existingUserSet.getItems().indexOf(item1));
+    assertEquals(4, existingUserSet.getPinned());
+    assertEquals(5, existingUserSet.getItems().size());
+    
+    //insert un-pinned items, some of which may exist (and can be pinned or not-pinned in the set)
+    newItems.clear();
+    //adding an existing pinned item in the request of un-pinned items
+    newItems.add(item1);
+    String item5="/05/123_unPinnedItem";
+    newItems.add(item5);
+    String item6Existing=existingUserSet.getItems().get(4);
+    newItems.add(item6Existing);
+    getUserSetService().insertMultipleItems(newItems, "4", 4, existingUserSet);
+    //check the new items
+    assertEquals(0, existingUserSet.getItems().indexOf(item2));
+    assertEquals(1, existingUserSet.getItems().indexOf(item4Existing));
+    assertEquals(2, existingUserSet.getItems().indexOf(item3));
+    assertEquals(3, existingUserSet.getItems().indexOf(item1));
+    assertEquals(4, existingUserSet.getPinned());
+    assertEquals(4, existingUserSet.getItems().indexOf(item5));
+    assertEquals(5, existingUserSet.getItems().indexOf(item6Existing));
+    assertEquals(4, existingUserSet.getPinned());
+    assertEquals(6, existingUserSet.getItems().size());
+    
+    //insert item to the last position
+    newItems.clear();
+    String item7="/07/123_unPinnedItem";
+    newItems.add(item7);
+    getUserSetService().insertMultipleItems(newItems, null, -1, existingUserSet);
+    //check the new items
+    assertEquals(6, existingUserSet.getItems().indexOf(item7));
+    assertEquals(4, existingUserSet.getPinned());
+    assertEquals(7, existingUserSet.getItems().size());
+    //insert item to the position grater than the total size of items
+    newItems.clear();
+    String item8="/08/123_unPinnedItem";
+    newItems.add(item8);
+    getUserSetService().insertMultipleItems(newItems, "100", 100, existingUserSet);
+    //check the new items
+    assertEquals(7, existingUserSet.getItems().indexOf(item8));
+    assertEquals(4, existingUserSet.getPinned());
+    assertEquals(8, existingUserSet.getItems().size());
+        
+  }
+
   // test conversion of pinned -> normal item
   @Test
   void insertAlreadyExistingPinnedItemAsNormalItem_EntityUserSets_withEditorUser()
diff --git a/set-web/src/main/java/eu/europeana/set/web/config/UserSetI18nConstants.java b/set-web/src/main/java/eu/europeana/set/web/config/UserSetI18nConstants.java
index adf41d19..4cae4336 100644
--- a/set-web/src/main/java/eu/europeana/set/web/config/UserSetI18nConstants.java
+++ b/set-web/src/main/java/eu/europeana/set/web/config/UserSetI18nConstants.java
@@ -18,6 +18,7 @@ private UserSetI18nConstants() {
     public static final String INVALID_HEADER_FORMAT  = "error.userset_invalid_header_format";
     public static final String INVALID_HEADER_VALUE   = "error.userset_invalid_header_value";
     public static final String INVALID_SUBJECT_VALUE   = "error.userset_subject_invalid_value";
+    public static final String INVALID_UNPINNED_ITEMS_POSITION = "error.userset_unpinned_items_position_invalid";
 
     public static final String USERSET_VALIDATION    			= "error.userset_validation";
     public static final String USERSET_DUPLICATION              = "error.userset_duplication";
diff --git a/set-web/src/main/java/eu/europeana/set/web/http/SwaggerConstants.java b/set-web/src/main/java/eu/europeana/set/web/http/SwaggerConstants.java
index 4f1770a7..46380dc8 100644
--- a/set-web/src/main/java/eu/europeana/set/web/http/SwaggerConstants.java
+++ b/set-web/src/main/java/eu/europeana/set/web/http/SwaggerConstants.java
@@ -12,6 +12,7 @@ private SwaggerConstants() {
     public static final String SAMPLES_JSONLD   = "Please find JSON-LD samples for user set in <a href=\"../jsp/template/jsonld.jsp\" target=\"_blank\">templates</a>. ";
     public static final String SEARCH_HELP_NOTE = "Identifier is a number.";
     public static final String INSERT_ITEM_NOTE = "Please create your insert item request using selected parameters.";
+    public static final String INSERT_MULTIPLE_ITEM_NOTE = "Please create your insert multiple items request using selected parameters.";
     public static final String PUBLISH_SET_NOTE = "Please create the request for publishing the set using the provided parameters.";
     public static final String CHECK_ITEM_NOTE  = "Check if item is already in a user set";
     public static final String DELETE_ITEM_NOTE = "Delete a item from the set ";
diff --git a/set-web/src/main/java/eu/europeana/set/web/service/UserSetService.java b/set-web/src/main/java/eu/europeana/set/web/service/UserSetService.java
index 211f0ef9..3e347440 100644
--- a/set-web/src/main/java/eu/europeana/set/web/service/UserSetService.java
+++ b/set-web/src/main/java/eu/europeana/set/web/service/UserSetService.java
@@ -10,6 +10,7 @@
 import eu.europeana.api.commons.web.exception.ApplicationAuthenticationException;
 import eu.europeana.api.commons.web.exception.HttpException;
 import eu.europeana.api.commons.web.exception.ParamValidationException;
+import eu.europeana.set.definitions.config.UserSetConfiguration;
 import eu.europeana.set.definitions.model.UserSet;
 import eu.europeana.set.definitions.model.search.UserSetFacetQuery;
 import eu.europeana.set.definitions.model.search.UserSetQuery;
@@ -131,13 +132,16 @@ UserSet fetchItems(UserSet storedUserSet, String sort, String sortOrder, int pag
     UserSet insertItem(String datasetId, String localId, String position, UserSet existingUserSet)
 	    throws ApplicationAuthenticationException, ItemValidationException;
 
+    public UserSet insertMultipleItems(List<String> items, String position, int itemsPosition, UserSet existingUserSet) 
+        throws ItemValidationException;
+
     /**
      * This method updates existing item list
      * 
      * @param existingUserSet
      * @return updated user set
      */
-    UserSet updateItemList(UserSet existingUserSet);
+    UserSet updateUserSetInMongo(UserSet existingUserSet);
 
     /**
      * search user sets using the given query and profile
@@ -257,4 +261,6 @@ ItemIdsResultPage buildItemIdsResultsPage(String setId, List<String> itemIds, in
 
     void validateGallerySize(UserSet webUserSet, int newItems) throws ItemValidationException;
 
+    UserSet updatePagination(UserSet userSet, UserSetConfiguration config);
+    
 }
\ No newline at end of file
diff --git a/set-web/src/main/java/eu/europeana/set/web/service/controller/jsonld/WebUserSetRest.java b/set-web/src/main/java/eu/europeana/set/web/service/controller/jsonld/WebUserSetRest.java
index b32ea3c9..a34ad74e 100644
--- a/set-web/src/main/java/eu/europeana/set/web/service/controller/jsonld/WebUserSetRest.java
+++ b/set-web/src/main/java/eu/europeana/set/web/service/controller/jsonld/WebUserSetRest.java
@@ -415,6 +415,7 @@ protected ResponseEntity<String> publishUnpublishUserSet(String identifier, Auth
     }
   }
 
+  @Deprecated
   @PutMapping(value = {"/set/{identifier}/{datasetId}/{localId}"},
       produces = {HttpHeaders.CONTENT_TYPE_JSONLD_UTF8, HttpHeaders.CONTENT_TYPE_JSON_UTF8})
   @Operation(description = SwaggerConstants.INSERT_ITEM_NOTE,
@@ -433,6 +434,21 @@ public ResponseEntity<String> insertItemIntoUserSet(
     return insertItemIntoUserSet(request, authentication, identifier, datasetId, localId, position);
   }
 
+  @PutMapping(value = {"/set/{identifier}/items"},
+      produces = {HttpHeaders.CONTENT_TYPE_JSONLD_UTF8, HttpHeaders.CONTENT_TYPE_JSON_UTF8})
+  @Operation(description = SwaggerConstants.INSERT_MULTIPLE_ITEM_NOTE,
+      summary = "Insert multiple items to an existing user set")
+  public ResponseEntity<String> insertMultipleItemsIntoUserSet(
+      @PathVariable(value = WebUserSetFields.PATH_PARAM_SET_ID) String identifier,
+      @RequestParam(value = WebUserSetFields.PATH_PARAM_POSITION, required = false) String position,
+      @RequestBody List<String> items,
+      HttpServletRequest request) throws HttpException {
+    // check user credentials, if invalid respond with HTTP 401,
+    // or if unauthorized respond with HTTP 403
+    Authentication authentication = verifyWriteAccess(Operations.UPDATE, request);
+    return insertMultipleItemsIntoUserSet(request, authentication, identifier, items, position);
+  }
+
   /**
    * This method validates input values, retrieves user set object and inserts item within user set
    * to given position or at the end if no valid position provided.
@@ -443,10 +459,10 @@ public ResponseEntity<String> insertItemIntoUserSet(
    * @param datasetId The identifier of the dataset, typically a number
    * @param localId The local identifier within the provider
    * @param position The position in the existin item list
-   * @param profileStr The profile definition
    * @return response entity that comprises response body, headers and status code
    * @throws HttpException
    */
+  @Deprecated
   protected ResponseEntity<String> insertItemIntoUserSet(HttpServletRequest request,
       Authentication authentication, String identifier, String datasetId, String localId, 
       String position) throws HttpException {
@@ -482,6 +498,83 @@ protected ResponseEntity<String> insertItemIntoUserSet(HttpServletRequest reques
       
       UserSet updatedUserSet =
           getUserSetService().insertItem(datasetId, localId, position, existingUserSet);
+      getUserSetService().updatePagination(updatedUserSet, getConfiguration());
+            
+      String serializedUserSetJsonLdStr = serializeUserSet(LdProfiles.MINIMAL, updatedUserSet);
+
+      String etag =
+          generateETag(updatedUserSet.getModified(), WebFields.FORMAT_JSONLD, getApiVersion());
+
+      // build response entity with headers
+      MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
+      headers.add(HttpHeaders.ALLOW, UserSetHttpHeaders.ALLOW_PPGHD);
+      headers.add(UserSetHttpHeaders.VARY, HttpHeaders.PREFER);
+      headers.add(UserSetHttpHeaders.PREFERENCE_APPLIED, LdProfiles.MINIMAL.getPreferHeaderValue());
+      headers.add(UserSetHttpHeaders.ETAG, etag);
+      return new ResponseEntity<>(serializedUserSetJsonLdStr, headers, HttpStatus.OK);
+
+    } catch (UserSetValidationException e) {
+      throw new RequestValidationException(UserSetI18nConstants.USERSET_VALIDATION,
+          new String[] {e.getMessage()}, e);
+    } catch (HttpException e) {
+      throw e;
+    } catch (RuntimeException | IOException e) {
+      throw new InternalServerException(e);
+    }
+  }
+
+  /**
+   * This method validates input values, retrieves user set object and inserts multiple items
+   * within user set to the given position or at the end if no valid position provided.
+   * 
+   * @param request
+   * @param authentication The Authentication object
+   * @param identifier The identifier of a user set
+   * @param items Items to be added to the set
+   * @param position The position in the existin item list
+   * @return response entity that comprises response body, headers and status code
+   * @throws HttpException
+   */
+  protected ResponseEntity<String> insertMultipleItemsIntoUserSet(HttpServletRequest request,
+      Authentication authentication, String identifier, List<String> items, String position) throws HttpException {
+    try {     
+      // check if the Set exists, if not respond with HTTP 404
+      // retrieve an existing user set based on its identifier
+      UserSet existingUserSet = getUserSetService().getUserSetById(identifier);
+
+      if (existingUserSet.isOpenSet()) {
+        // cannot add items to open sets
+        throw new RequestValidationException(UserSetI18nConstants.USER_SET_OPERATION_NOT_ALLOWED,
+            new String[] {"'Insert item to existing user set'", "open"});
+      }
+
+      // if set is not entity best item set and position is "pin", throw exception
+      if (!existingUserSet.isEntityBestItemsSet()
+          && StringUtils.equals(position, WebUserSetFields.PINNED_POSITION)) {
+        throw new RequestValidationException(UserSetI18nConstants.USER_SET_OPERATION_NOT_ALLOWED,
+            new String[] {"Pinning item ", existingUserSet.getType()});
+      }
+      
+      int itemsPosition=UserSetUtils.parseItemsPosition(position);
+      if(!StringUtils.equals(position, WebUserSetFields.PINNED) && itemsPosition>=0 && itemsPosition < existingUserSet.getPinned()) {
+        throw new RequestValidationException(UserSetI18nConstants.INVALID_UNPINNED_ITEMS_POSITION, null);
+      }
+      
+      // check visibility level for given user
+      getUserSetService().verifyPermissionToUpdate(existingUserSet, authentication, true);
+
+      // for entity user sets, add users with 'editor' role as contributors
+      addContributorForEntitySet(existingUserSet, authentication);
+
+      // check timestamp if provided within the “If-Match” HTTP header, if false
+      // respond with HTTP 412
+      String eTagOrigin =
+          generateETag(existingUserSet.getModified(), WebFields.FORMAT_JSONLD, getApiVersion());
+      checkIfMatchHeader(eTagOrigin, request);
+      
+      UserSet updatedUserSet =
+          getUserSetService().insertMultipleItems(items, position, itemsPosition, existingUserSet);
+      getUserSetService().updatePagination(updatedUserSet, getConfiguration());
       
       String serializedUserSetJsonLdStr = serializeUserSet(LdProfiles.MINIMAL, updatedUserSet);
 
@@ -661,7 +754,9 @@ protected ResponseEntity<String> deleteItemFromUserSet(Authentication authentica
       existingUserSet.getItems().remove(newItem);
 
       // update an existing user set
-      UserSet updatedUserSet = getUserSetService().updateItemList(existingUserSet);
+      UserSet updatedUserSet = getUserSetService().updateUserSetInMongo(existingUserSet);
+      //update pagination fields (used only for the response serialization)
+      getUserSetService().updatePagination(updatedUserSet, getConfiguration());
       
       // serialize to JsonLd
       String serializedUserSetJsonLdStr = serializeUserSet(LdProfiles.MINIMAL, updatedUserSet);
diff --git a/set-web/src/main/java/eu/europeana/set/web/service/impl/BaseUserSetServiceImpl.java b/set-web/src/main/java/eu/europeana/set/web/service/impl/BaseUserSetServiceImpl.java
index 3076507f..060b5d6f 100644
--- a/set-web/src/main/java/eu/europeana/set/web/service/impl/BaseUserSetServiceImpl.java
+++ b/set-web/src/main/java/eu/europeana/set/web/service/impl/BaseUserSetServiceImpl.java
@@ -62,6 +62,13 @@ public abstract class BaseUserSetServiceImpl implements UserSetService {
   private SearchApiClient setApiService = new SearchApiClientImpl();
 
   Logger logger = LogManager.getLogger(getClass());
+  
+  
+  //update the pagination fields of the set (used only for the serialization to the output)
+  @Override
+  public UserSet updatePagination(UserSet userSet, UserSetConfiguration config) {
+    return userSetUtils.updatePagination(userSet, config);
+  }
 
   protected PersistentUserSetService getMongoPersistence() {
     return mongoPersistance;
@@ -501,6 +508,8 @@ private void validateAndSetItems(UserSet storedUserSet, UserSet userSetUpdates)
     }
   }
 
+  //this method is to be deprecated when the new items insert is used
+  @Deprecated
   protected void validateItems(List<String> items) throws ItemValidationException {
     if(items==null || items.isEmpty()) {
       return;
@@ -518,7 +527,35 @@ protected void validateItems(List<String> items) throws ItemValidationException
       throw new ItemValidationException(UserSetI18nConstants.USERSET_ITEM_INVALID_FORMAT, new String[] {invalidItems.toString()} );
     }
   }
-  
+
+  //items can be either a uri or a record identifier (e.g. "/1234/XPTO_2")
+  protected void validateItemsStrings(List<String> items) throws ItemValidationException {
+    if(items==null || items.isEmpty()) {
+      return;
+    }
+    List<String> invalidItems = new ArrayList<>();
+    for(String item : items) {
+      try {
+        if(item.startsWith(getConfiguration().getItemDataEndpoint())) {
+          String itemWithoutBase = item.replace(getConfiguration().getItemDataEndpoint(), "");
+          if(!itemWithoutBase.startsWith("/")) {
+            itemWithoutBase = "/" + itemWithoutBase;
+          }
+          validateItemPartial(itemWithoutBase);
+        }
+        else {
+          validateItemPartial(item);
+        }
+      }
+      catch (ItemValidationException ex) {
+        invalidItems.add(item);
+      }
+    }
+    if(invalidItems.size()>0) {
+      throw new ItemValidationException(UserSetI18nConstants.USERSET_ITEM_INVALID_FORMAT, new String[] {invalidItems.toString()} );
+    }
+  }
+
   protected void validateItemWhole(String item) throws ItemValidationException {
     if(!item.startsWith(getConfiguration().getItemDataEndpoint())) {
       throw new ItemValidationException(UserSetI18nConstants.USERSET_ITEM_INVALID_FORMAT, new String[] {item});
diff --git a/set-web/src/main/java/eu/europeana/set/web/service/impl/UserSetServiceImpl.java b/set-web/src/main/java/eu/europeana/set/web/service/impl/UserSetServiceImpl.java
index 3e6c9314..fffb7b3f 100644
--- a/set-web/src/main/java/eu/europeana/set/web/service/impl/UserSetServiceImpl.java
+++ b/set-web/src/main/java/eu/europeana/set/web/service/impl/UserSetServiceImpl.java
@@ -26,7 +26,6 @@
 import eu.europeana.api.commons.web.exception.HttpException;
 import eu.europeana.api.commons.web.exception.InternalServerException;
 import eu.europeana.api.commons.web.exception.ParamValidationException;
-import eu.europeana.set.definitions.config.UserSetConfigurationImpl;
 import eu.europeana.set.definitions.exception.UserSetAttributeInstantiationException;
 import eu.europeana.set.definitions.exception.UserSetInstantiationException;
 import eu.europeana.set.definitions.model.UserSet;
@@ -227,6 +226,92 @@ int validatePosition(String position, List<String> items, int pinnedItems) {
     }
     return positionInt;
   }
+  
+  int calculatePosition(int position, List<String> items) {
+    int positionFinal = items.size();
+    if (position >= 0 && position < items.size()) {
+      positionFinal = position;
+    }
+    return positionFinal;
+  }
+
+  public UserSet insertMultipleItems(List<String> items, String position, int itemsPosition, UserSet existingUserSet) 
+      throws ItemValidationException {
+    
+    validateItemsStrings(items);
+    
+    // check if the position is "pin" and is a EntityBestItem set then
+    // insert the item at the 0 position
+    UserSet userSet;
+
+    if (WebUserSetModelFields.PINNED_POSITION.equals(position)) {
+      userSet=updateItemsFromPinned(existingUserSet, items);
+    } else {
+      userSet=updateItemsFromUnpinned(existingUserSet, items, itemsPosition);
+    }
+    
+    return userSet;
+  }  
+  
+  private UserSet updateItemsFromPinned(UserSet existingUserSet, List<String> items) {
+    List<String> usersetItems=existingUserSet.getItems();
+    if(usersetItems==null) {
+      usersetItems=new ArrayList<>();
+    }
+    else {    
+      /*remove all duplicate items from the set and count the number 
+      of removed pinned items, to change the pinned field
+      */
+      for(String newItem : items) {
+        int itemindex=usersetItems.indexOf(newItem);
+        if(itemindex>=0) {
+          if(itemindex < existingUserSet.getPinned()) {
+            existingUserSet.setPinned(existingUserSet.getPinned() - 1);
+          }
+          usersetItems.remove(newItem);
+        }
+      }
+    }
+    
+    usersetItems.addAll(0, items);
+    existingUserSet.setPinned(existingUserSet.getPinned() + items.size());
+    UserSet updatedSet=updateUserSetInMongo(existingUserSet);
+    return updatedSet;
+  }
+  
+  private UserSet updateItemsFromUnpinned(UserSet existingUserSet, List<String> items, int position) throws ItemValidationException {
+    List<String> usersetItems=existingUserSet.getItems();
+    List<String> newItemsCopy=new ArrayList<>(items);
+    if(usersetItems==null) {
+      usersetItems=new ArrayList<>();
+    }
+    else {
+      /*remove from the new items the ones that were pinned before
+       *and from the user set the ones that are duplicates
+      */
+      for(String newItem : newItemsCopy) {
+        int itemindex=usersetItems.indexOf(newItem);
+        if(itemindex>=0) {
+          if(itemindex < existingUserSet.getPinned()) {
+            items.remove(newItem);
+          }
+          else {
+            usersetItems.remove(newItem);
+          }
+        }
+      }
+      //validation of the number of items for type Gallery 
+      if(existingUserSet.isGallery() && (usersetItems.size() + items.size()) > getConfiguration().getGalleryMaxSize()) {
+        throw new ItemValidationException(UserSetI18nConstants.USERSET_ITEMS_LIMIT_REACHED, 
+            new String[] {String.valueOf(getConfiguration().getGalleryMaxSize())} );  
+      }  
+    }
+    
+    int positionFinal=calculatePosition(position, usersetItems);
+    usersetItems.addAll(positionFinal, items);
+    UserSet updatedSet=updateUserSetInMongo(existingUserSet);
+    return updatedSet;
+  }
 
   /*
    * (non-Javadoc)
@@ -261,7 +346,7 @@ public UserSet insertItem(String datasetId, String localId, String position,
           validatePosition(position, existingUserSet.getItems(), existingUserSet.getPinned());
       userSet = insertItem(existingUserSet, newItem, positionInt, false);
     }
-    getUserSetUtils().updatePagination(userSet, getConfiguration());
+    //getUserSetUtils().updatePagination(userSet, getConfiguration());
     return userSet;
   }  
 
@@ -291,7 +376,7 @@ private UserSet insertItem(UserSet existingUserSet, String newItem, int position
       // add item && create item list if needed
       addNewItemToList(existingUserSet, finalPosition, newItem);
       updatePinCount(existingUserSet, pinnedItem, -1);
-      extUserSet = updateItemList(existingUserSet);
+      extUserSet = updateUserSetInMongo(existingUserSet);
     } else {
       // replace item
       int oldPosition = existingUserSet.getItems().indexOf(newItem);
@@ -302,7 +387,7 @@ private UserSet insertItem(UserSet existingUserSet, String newItem, int position
       } else {
         replaceItem(existingUserSet, finalPosition, newItem);
         updatePinCount(existingUserSet, pinnedItem, oldPosition);
-        extUserSet = updateItemList(existingUserSet);
+        extUserSet = updateUserSetInMongo(existingUserSet);
       }
     }
 
@@ -340,7 +425,7 @@ private void updatePinCount(UserSet existingUserSet, boolean pinnedItem, int old
    * @see eu.europeana.set.web.service.UserSetService#updateItemList(eu.europeana.set.
    * definitions.model.UserSet)
    */
-  public UserSet updateItemList(UserSet existingUserSet) {
+  public UserSet updateUserSetInMongo(UserSet existingUserSet) {
     // update total
     updateTotal(existingUserSet);
     // generate and add a created and modified timestamp to the Set
@@ -350,7 +435,7 @@ public UserSet updateItemList(UserSet existingUserSet) {
     // update an existing user set. merge user sets - insert new fields in existing
     // object
     UserSet updatedUserSet = getMongoPersistence().update((PersistentUserSet) existingUserSet);
-    getUserSetUtils().updatePagination(updatedUserSet, getConfiguration());
+    //getUserSetUtils().updatePagination(updatedUserSet, getConfiguration());
     return updatedUserSet;
   }
 
diff --git a/set-web/src/main/resources/messages_en.properties b/set-web/src/main/resources/messages_en.properties
index 6511af35..6cdccfa7 100644
--- a/set-web/src/main/resources/messages_en.properties
+++ b/set-web/src/main/resources/messages_en.properties
@@ -50,6 +50,7 @@ error.no_entity_userset_found=No entity user set found in database.
 error.no_elevation_generated=There are no items present in the entity user sets OR entity references are invalid.
 error.userset_validation_search_request_not_valid=Error serialising the search API request body.
 error.userset_lock_not_in_effect=No write lock in effect!
+error.userset_unpinned_items_position_invalid=Position value for inserting un-pinned items should come after the pinned items.
 #500
 error.server_unexpected_error=An unexpected error occurred on server!