Rehabilitation of the anterior cruciate ligament (ACL) reconstructed knee continues to be a topic of intense interest among surgeons and therapists. Since 1987, over 880 patients who have undergone ACL reconstruction using the central one-third of the bone patellar tendon bone graft have followed our accelerated rehabilitation protocol. Follow-up of the patients reveals early return to athletic activity and maintenance of long-term stability. Our 1987 accelerated rehabilitation program continues to be modified, with less constraints placed on the postoperative patient in our present rehabilitation protocol. These recent changes are once again prompted by noncompliant patients who, with close follow-up evaluation, continue to yield excellent results. Our present accelerated rehabilitation protocol is divided into four phases. The initial phase encompasses the preoperative period. The second phase involves the initial 2 weeks post ACL reconstruction. The third phase dates from 2-5 weeks postoperation, and the final phase (greater than 5 weeks) involves a safe return to athletic play. Our goal with the accelerated rehabilitation protocol remains to decrease postoperative complications without jeopardizing the long term stability of the ACL reconstructed knee. J Orthop Sports Phys Ther 1992;15(6):303-308.