Medial and lateral gastrocnemius flaps are large flaps that can be taken in the lower extremity with no delay. They have a wide arc of rotation from above the patella in the thigh to the upper portion of the lower tibia. Both flaps can be taken simultaneously. They can cover extremely large defects of the anterior leg or knee. The use of these flaps with their ready availability, excellent blood supply, and wide range of coverage has tremendously facilitated immediate correction of severe injuries of the knee and lower leg.