diff --git a/test_tools/test_events/validate_timestamp_conversion.csv b/test_tools/test_events/validate_timestamp_conversion.csv
new file mode 100644
index 0000000000..845aa9ec6f
--- /dev/null
+++ b/test_tools/test_events/validate_timestamp_conversion.csv
@@ -0,0 +1,4 @@
+"message","timestamp","datetime","timestamp_desc","data_type"
+"Checking timestamp conversion","1331698658000000","2012-03-14T04:17:38+00:00","Time Logged","This event has timestamp"
+"Checking timestamp conversion","1658689261000000","2022-07-24T19:01:01+0000","Time Logged","This event has timestamp"
+"Make sure message is same","1437789661000000","2015-07-25 02:01:01+00:00","Logging","This data_type should stay the same"
diff --git a/timesketch/lib/utils_test.py b/timesketch/lib/utils_test.py
index 871f420486..8e7ca0e219 100644
--- a/timesketch/lib/utils_test.py
+++ b/timesketch/lib/utils_test.py
@@ -180,6 +180,7 @@ def test_missing_timestamp_csv_file(self):
         """Test for parsing datetime values in CSV file"""
 
         # Test that a timestamp is generated if missing.
+
         expected_output = {
             "message": "No timestamp",
             "datetime": "2022-07-24T19:01:01+00:00",
@@ -196,6 +197,41 @@ def test_missing_timestamp_csv_file(self):
             expected_output,
         )
 
+    def test_timestamp_is_ISOformat(self):
+        """Test that timestamp values in CSV file are not altered"""
+
+        # Make sure timestamp is processed correctly, and the format is not altered
+        expected_outputs = [
+            {
+                "message": "Checking timestamp conversion",
+                "timestamp": 1331698658000000,
+                "datetime": "2012-03-14T04:17:38+00:00",
+                "timestamp_desc": "Time Logged",
+                "data_type": "This event has timestamp",
+            },
+            {
+                "message": "Checking timestamp conversion",
+                "timestamp": 1658689261000000,
+                "datetime": "2022-07-24T19:01:01+00:00",
+                "timestamp_desc": "Time Logged",
+                "data_type": "This event has timestamp",
+            },
+            {
+                "message": "Make sure message is same",
+                "timestamp": 1437789661000000,
+                "datetime": "2015-07-25T02:01:01+00:00",
+                "timestamp_desc": "Logging",
+                "data_type": "This data_type should stay the same",
+            },
+        ]
+        results = iter(
+            read_and_validate_csv(
+                "test_tools/test_events/validate_timestamp_conversion.csv"
+            )
+        )
+        for output in expected_outputs:
+            self.assertDictEqual(next(results), output)
+
     def test_invalid_JSONL_file(self):
         """Test for JSONL with missing keys in the dictionary wrt headers mapping"""
         linedict = {"DT": "2011-11-11", "MSG": "this is a test"}