The most commonly used graft source for anterior cruciate ligament reconstruction is the autogenous bone- patellar tendon-bone graft unit. Despite a good success record, intraoperative technical errors and postoperative complications have been known. Author analyzed intraoperative technical errors and postoperative complications, in 44 patients who were treated at the department of orthopaedic surgery, chosun university hospital from Jan. 1994 to Jun. 1996. The most common intraoperative technical errors was screw graft divergency in 5 cases. Other intraoperative technical errors were too anteriorly location of femoral tunnel in 1 case, too anteriorly location of tibial k femora) tunne.l both in 1 case, graft tunnel mismatching in 1 case, graft pullout in 1 case and partial destruction of posterior cortex of femoral tunnel in 1 case, fracture of the bone plug in 1 case. The most common postoperative complication was patellar tendinitis in 20 cases (45.5%). Other postoperative complications were anterior knee pain in 14 case. (31.8%), patellar crepitation in 12 cases (27.3%), quadriceps atrophy in 9 cases (20.5%), arthrofibrosis in 3 cases and graft failure in 2 cases. Author concluded the causes of intraoperative complications were technical errors, and anteriorly location of graft tunnel is most influenced factor to final fuctional results. To eliminate the postoperative complications, intraoperative technical errors should be avoided and also accelerated rehabilitation should be done.