Patellar tendon graft has been the most frequently used material in anterior cruciate ligament (ACL) reconstruction, but the hamstring tendons have been increasingly used as well; however, which graft is to be preferred is not adequately supported by existing clinical studies. In this prospective randomized clinical trial, the study hypothesis was that the hamstring tendons are equally good graft material as the patellar tendon in ACL reconstruction. Ninety-nine patients with laxity due to a torn ACL underwent arthroscopically assisted reconstruction with graft randomization according to their birth year to either patellar tendon with metal interference screw fixation or double looped semitendinosus and gracilis tendons with fixation similar to the Endobutton technique using a titanium metal plate suspension proximally and screw-washer postdistally. Excluding preoperative Lysholm knee score, there were no significant differences between the two groups in the preoperative and operative data. A standard rehabilitation regimen was used for all the patients, including immediate postoperative mobilization without a knee brace, protected weight bearing for 2 weeks, and return to full activity at 6-12 months postoperatively. Forty patients in the patellar tendon group and 39 patients in the hamstring tendon group were available for clinical evaluation at median 5 years after surgery (ranges 3 years 11 months-6 years 7 months). The results revealed no statistically significant differences with respect to clinical and instrumented laxity testing, isokinetic muscle torque measurements, International Knee Documentation Committee ratings, Lysholm (knee score), Tegner (activity level) and Kujala patellofemoral knee scores. There was an enlargement of the drill tunnels, statistically more in the hamstring tendon group, but no increase from 2 to 5 years in either group. Narrowing of the joint spaces (IKDC measurement method) from 2 to 5 years postoperatively was seen in both the groups, however, without difference between the two groups.