Given that the compilers for each .NET language generate the same intermediate language, use the same runtime, build the same kind of types and use the same primitive types, it is possible to build programs where the code is written in different .NET languages.

For example, a Visual Basic.NET programmer can create a class that derives from a C# class and overrides some of its virtual methods; or a C# programmer can handle an exception thrown by a method being applied to an object of an Eiffel class; and so on.