Purpose: To evaluate the clinical results of anterior cruciate ligament (ACL) reconstruction and to know the results of physeal injury by transphyseal tunnel in adolescents who had remaining growth potential. Materials and Methods : This study involved 12 patients under 19 years old out of 445 patients, who underwent ACL reconstruction between 1993 and 2001. The mean age at the time of operation was 15.9 $(13.1~16.9)$ years and fellow-up period was 45.1 $(24~120.6)$ months in avrarge. Autologous quadrupled hamstring tendon was used as graft in 11 cases and bone-patellar tendon-bone in 1 case. Clinical results were evaluated by Lysholm Knee Scoring Scale, range of motion and return to preinjury sports activities. Radiologic results were evaluated by $Telos^{circledR}$ device. Bone maturity were analyzed by chronological age, standing height and the width of growth plate in AP and lateral view of knee joint at preoperatively. The growth disturbances were evaluated by measuring femorotibial angle, anatomical and mechanical lateral distal femoral angle, mechanical medial proximal tibial angle and leg length and by comparing those of uninjured site in last follow-up teleoroentgenogram. Results : The mean Lysholm Knee score was 51 $(25~63)$points preoperatively and 98 $(94~100)$ points at last follow up. The mean anterior displacement of the tibia by using $Telos^{circledR}$ device was improved from 13.5 $(6~27)$ mm to 2.9 $(1~4)$ mm and there were no significant instabilities of the knee in all cases. There were no leg length discrepancies over 1 cm and no statistically significant abnormal alignment of the knee joint in all cases. Conclusion: ACL reconstruction using transphyseal tunnel for restoring stability and knee function is assumed as a good mettled of treatment without significant leg length discrepancy and abnormal alignment of the knee joint.