Although .NET is great in hiding whether a process is 32 or 64 bits sometimes you still need to know this. Most likely when using interop. You cannot interop a 64 bit .NET and a 32 bit dll and vice versa!
Fortunately the IntPtr.Size property can be used for this.
if ( IntPtr.Size == 8 ) { // Pointer is 8 bytes -> 64 bit } if ( IntPtr.Size == 4 ) { // Pointer is 4 bytes -> 32 bit }