diff --git a/Src/IronPython/Runtime/Types/NewTypeMaker.cs b/Src/IronPython/Runtime/Types/NewTypeMaker.cs
index b878a8e91..ca0f96ffe 100644
--- a/Src/IronPython/Runtime/Types/NewTypeMaker.cs
+++ b/Src/IronPython/Runtime/Types/NewTypeMaker.cs
@@ -540,6 +540,7 @@ private void ImplementCustomTypeDescriptor() {
             ImplementInterface(typeof(ICustomTypeDescriptor));
 
             foreach (MethodInfo m in typeof(ICustomTypeDescriptor).GetMethods()) {
+                if (!m.IsAbstract) continue;
                 ImplementCTDOverride(m);
             }
         }