diff --git a/dds/idl/dds_generator.h b/dds/idl/dds_generator.h
index e0d9225c240..d09d7a6a9bb 100644
--- a/dds/idl/dds_generator.h
+++ b/dds/idl/dds_generator.h
@@ -538,7 +538,9 @@ inline std::string to_cxx_type(AST_Type* type, std::size_t& size)
   const AstTypeClassification::Classification cls = AstTypeClassification::classify(type);
   if (cls & AstTypeClassification::CL_ENUM) {
     size = 4;
-    return "ACE_CDR::ULong";
+    // Using the XTypes definition of Enums, this type is signed.
+    // It contradicts the OMG standard CDR definition.
+    return "ACE_CDR::Long";
   }
   if (cls & AstTypeClassification::CL_STRING) {
     return string_type(cls);