MSDN says: Windows NT 4.0 and earlier, Windows 95/98/Me: There is no way to get the thread handle from the thread identifier. If the handles were made available this way, the owning process could fail because another process unexpectedly performed an operation on one of its threads, such as suspending it, resuming it, adjusting its priority, or terminating it. Instead, you must request the handle from the thread creator or the thread itself. A thread can use the GetCurrentThread function to retrieve a pseudo handle to its own thread object. This pseudo handle is valid only for the calling process; it cannot be inherited or duplicated for use by other processes. To get the real handle to the thread, given a pseudo handle, use the DuplicateHandle function.