I think you People forgot the Basic .NET Frame work. As all the Application are in a Compiled form even though you are using VB or C# in different projects there wont be any problem in calling. All the functionality will be similar as the application consider only the compield native code. Hai Adrian De Battista you can call the functions from C# - VB or VB - C# as if you are calling C# - C# or VB - VB Regards, Nagendra Rao S.V