Purpose : The purpose of this study was to compare the postoperative success and stability of arthroscopically assisted anterior cruciate ligament(ACL) reconstructions using central one third bone-patellar-tendon bone(BPB) autograft versus quadrupled semitendinos-us(ST) autograft as the medium term review. Materials and Methods : Eighty patients(40 BPBs,40 STs) with isolated ACL injury were available for a mean follow up of 49.4 months(BPB) and 48.8 months(ST). There was no significant difference between the two groups with respect to age and sex. We compare the final results between two groups with respect to subjective Lysholm score, objective laxity including anterior drawer test, Lachman test, pivot shift test, KT-2000 measurements and International Knee Documentation Committee(IKDC) evaluation system. Results : Postoperatively, positive anterior drawer test was found in $22.5\%;and;27.5\%$, positive Lachman test was found in $30.0\%$ and $25.0\%$ and positive pivot shift test was found in $15\%;and;20\%$ of the ST and BPB group, respectively(p>0.05). Mean side to side difference of KT-2000 at 20 lbs was 2.2 mm for the ST group and 2.1 mm for the BPB group. There was no significant difference between the two groups about Lysholm score(>0.05). Anterior knee pain was knee common in the BPB group. Eighty-three percent of the patients were nearly normal according to the IKDC grade in both groups. Conclusion : We consider that autogenous semitendinosus tendon is a good alternative subsititute in ACL reconstruction together with the bone-patellar tendon-bone autograft.