Forty-one patients in whom operative reconstruction of a torn anterior cruciate ligament had been performed by one surgeon with use of a double-looped semitendinosus and gracilis hamstring graft were studied to determine (1) if a brace-free rehabilitation program compromised the early stability of the knee; (2) if the stability of the knee deteriorated between four months, when the patient returned to unrestricted activities, and two years; and (3) if the function of the treated knee was completely restored by four months after the operation. The graft was placed arthroscopically, without impingement by the intercondylar roof, and was fixed within the tibial tunnel to conserve the length of the graft. The stability and function of thirty-seven of the knees were assessed at four months as part of a larger prospective study. Four patients chose not to return for the four-month evaluation. The patients returned to unrestricted sports and work activities after the four-month evaluation. At two years, all forty-one patients were evaluated.At four months, after completion of the brace-free rehabilitation program, thirty-three (82 per cent) of the thirty-seven patients had an absent pivot shift and a normal Lachman test. Twenty-eight (88 per cent) of thirty-four knees had less than three millimeters of difference in laxity compared with the contralateral knee, as determined by testing at the maximum manual force with use of a KT-1000 arthrometer. Stability remained unchanged at two years, justifying the early return to vigorous activities at four months. The girth of the thigh, the extension of the knee, and the Lysholm and Gillquist score were the same at four months as at two years, verifying the success of the brace-free intensive rehabilitation program in the restoration of early function to the treated knee. However, some continued improvement was observed in the performance of the one-leg-hop for distance test between four months and two years.