PURPOSE: To compare clinical and radiographic results of anterior cruciate ligament (ACL) reconstruction using modified transtibial technique (mTT), anteromedial (AM) portal technique and outside-in (OI) technique. MATERIALS AND METHODS: From March 2007 to December 2012, ACL reconstruction was performed using the mTT, AM portal technique and OI technique in 20 patients each. Anteroposterior and rotational stability were assessed using the GNRB arthrometer and pivot-shift test. Femoral tunnel obliquity was measured on the anteroposterior and lateral radiographs. RESULTS: Tegner score, Lysholm score, International Knee Documentation Committee score, pivot-shift test were improved at final follow-up in all three groups. However, statistical difference was not shown. Side-to-side difference in GNRB arthrometer was average of 1.4 mm, 1.0 mm and 0.9 mm in mTT, AM and OI group, showing the signicant difference between mTT and AM/OI groups (p<0.001). The mean femoral tunnel obliquity was 56.4degrees in the mTT group, 39.4degrees in the AM group and 33.6degrees in the OI group, showing significant intergroup difference (p<0.001). It showed the significant difference among three groups (p<0.001). CONCLUSIONS: Clinical results were improved in all three groups. Femoral tunnel obliquity in AM and OI were more horizontal on the coronal plane. They are thought to have more benefits in oblique positioning of the grafted ACL in rotational stability; however, there was no significant difference among three techniques in pivot-shift test to assess the rotational stability in this study.