The standard gluteus maximus myocutaneous flap, though an excellent procedure for coverage of sacral soft-tissue defects, has several disadvantages. It is usually quite bulky, and risks hip instability in the ambulatory patient. Bilateral gluteus maximus myocutaneous advancement flaps obviate these problems. The superior half of each gluteus maximus muscle, with overlying skin island, is released from its origin and insertion. The superior gluteal artery is identified and preserved. Each myocutaneous unit may be advanced to the midline. The line of cleavage between units preserves normal contour. Donor-site deformity is closed in the V-Y advancement fashion. Hip instability is thus avoided. This technique is useful in the management of sacral defects in the ambulatory patient.