You ask a loaded question. C# is merely a language and does not require the .NET Framework. The process of compiling it requires a compiler, which may or may not itself take a dependency on the .NET Framework (Microsoft's C# compiler does not -- it is written in native code). Your program will need to reference some assembly where types, classes, and methods can be found for your use. You can remove system.dll and mscorlib.dll from your references list and reference your own assemblies. So you can avoid dependencies on the .NET Framework if you really work at it. But in the end, unless you have a C# compiler that compiles programs to native code you still have a dependency on the CLR.