diff --git a/src/Engine/ProtoCore/Lang/Type.cs b/src/Engine/ProtoCore/Lang/Type.cs
index fa2d72d88d3..50be014c287 100644
--- a/src/Engine/ProtoCore/Lang/Type.cs
+++ b/src/Engine/ProtoCore/Lang/Type.cs
@@ -121,6 +121,15 @@ public class TypeSystem
         public Dictionary<ProtoCore.DSASM.AddressType, int> addressTypeClassMap { get; set; }
         private static Dictionary<PrimitiveType, string> primitiveTypeNames;
 
+        private static readonly Dictionary<string, string> clrToDSTypeMap = new Dictionary<string, string>
+        {
+            { typeof(string).FullName, "string" },
+            { typeof(long).FullName, "int" },
+            { typeof(double).FullName, "double" },
+            { typeof(bool).FullName, "bool" },
+            { typeof(char).FullName, "char" }
+        };
+
         public TypeSystem()
         {
             SetTypeSystem();
@@ -314,7 +323,13 @@ public string GetType(int UID)
         public int GetType(string ident)
         {
             Validity.Assert(null != classTable);
-            return classTable.IndexOf(ident);
+            var index = classTable.IndexOf(ident);
+            if (index != Constants.kInvalidIndex) return index;
+
+            if(clrToDSTypeMap.TryGetValue(ident, out string dsType))
+                return classTable.IndexOf(dsType);
+
+            return Constants.kInvalidIndex;
         }
 
         public int GetType(StackValue sv)
diff --git a/test/Engine/ProtoTest/Associative/BuiltinMethodsTest.cs b/test/Engine/ProtoTest/Associative/BuiltinMethodsTest.cs
index 0ca49cf5a03..14de539b362 100644
--- a/test/Engine/ProtoTest/Associative/BuiltinMethodsTest.cs
+++ b/test/Engine/ProtoTest/Associative/BuiltinMethodsTest.cs
@@ -225,6 +225,27 @@ public void BIM10_RemoveIfNot()
             thisTest.Verify("t", 2);
         }
 
+        [Test]
+        //Test "RemoveIfNot()"
+        public void List_RemoveIfNot_CLRType()
+        {
+            String code =
+@"import(""BuiltIn.ds"");
+a = [""This is "",""a very complex "",""array"",1,2.0,3,false,4.0,5,6.0,true,[2,3.1415926],null,false,'c'];
+b = List.RemoveIfNot(a, ""System.Int64"");
+c = List.RemoveIfNot(a, ""System.Double"");
+d = List.RemoveIfNot(a, ""System.Boolean"");
+e = List.RemoveIfNot(a, ""System.Char"");
+f = List.RemoveIfNot(a, ""System.String"");
+";
+            ExecutionMirror mirror = thisTest.RunScriptSource(code);
+            thisTest.Verify("b", new int[] { 1, 3, 5 });
+            thisTest.Verify("c", new double[] { 2.0, 4.0, 6.0 });
+            thisTest.Verify("d", new bool[] { false, true, false });
+            thisTest.Verify("e", new char[] { 'c' });
+            thisTest.Verify("f", new string[] { "This is ", "a very complex ", "array" });
+        }
+
         [Test]
         //Test "Reverse()"
         public void BIM11_Reverse()