The Microsoft.NET Framework 3.0, or just .NET 3.0, has been released by Microsoft as well as the Visual Studio 2005 extensions for .NET 3.0 and the .NET 3.0 SDK. The downloads are available for Windows XP, Windows Server 2003 and Windows Vista where applicable.

The .NET 3.0 is .NET 2.0 extended with new technologies such as Windows Presentation Foundation, Windows Communication Foundation, Windows Workflow Foundation and Windows CardSpace.