Endoscopic ACL reconstruction using bone-patellar tendon-bone has been considered the gold standard in the field of reconstructive ACL surgery. Technically, graft must be placed at isometric point. But it is difficult to evaluate the placement of graft postoperatively. The purpose of this study is to determine the radiological ideal position of graft by comparing postoperative results with the graft placement. Seventy cases of endoscopic ACL reconstruction were reviewed and classified according to the femoral and tibial graft position on radiologic imaging. The femoral graft position was classified in relation to angle of graft on anterior position view and distance from posterior margin of graft to the inner surface of posterior cortex on lateral view. The tibial graft position was classified in relation to intercondylar eminence on anterior posterior view and lateral view. Knee score (modified Marshall, Lysholum), manual anterior instability test (Lachman test, Pivot shift test) and arthrometer measurement were checked to evaluate postoperative results in each case. The results of this study implicate that knee joint in which femoral graft was oriented at direction of 11 o clock centring around 68 degree respect to tibial joint and placed within 3mm from posterior cortex showed higher knee score and lesser laxity. In cases of tibial side, the graft oriented to intercondylar eminence (AP view) and placed anterior to intercondylar eminence (lateral view) showed higher knee score and lesser laxity.