OBJECTIVE To investigate the outcome of anterior cruciate ligament (ACL) by free autograft of middle one third of bone-patellar tendon-bone complex which was formed by lower edge of patella, middle one third of patellar tendon, and tibial tubercle. METHODS From April 1994 to August 1996, ACL reconstruction by bone-patellar tendon-bone complex was performed in 8 patients with ACL injury. RESULTS All cases were followed up 5 months to 3 years, averaged 26 months, excellent results were obtained in 4 cases, better in 3 cases and moderate in 1 case. The Lanchman test and/or anterior drawer test were positive in 8 cases preoperatively and only 1 case was positive postoperatively. Instability existed in 5 cases preoperatively were disappeared after operation. All patients could basically meet the demands of daily life. CONCLUSION Reconstruction of ACL by free autograft of middle one third of bone-patellar tendon-bone complex is an effective method for the restoration of stability in knee joint.