Functioning free muscle transfer to the upper extremity is an extremely complex and difficult procedure. It is useful only in selected cases that require significant skeletal muscle replacement and fulfill stringent criteria. The operation itself is performed by means of a two-team approach. Attention to detail is paramount if success is to be achieved. Careful placement of the muscle origin and insertion under appropriate tension is a key feature of the procedure. Precise microvascular anastomoses and microneural coaptations must be done. A time-intensive rehabilitation program is needed to gain as much function from the muscle as possible. Although not perfect, free muscle transfer does provide substantial improvement from a functional standpoint for these unfortunate patients.