Yes you can an extension method within inside an extension method. public static class ExtensionClass1 { public static string Info<T> (this T obj) where T:class { return obj.MoreInfo<T>() + ":" + obj.GetType().Name; } } public static class ExtensionClass2 { public static string MoreInfo<T>(this object obj) where T: class { return obj.GetType().Assembly.FullName; } } Tariq A Karim http://moplah.blogspot.com/