ACL reconstruction with patellar tendon graft has become a standard procedure. The graft can be inserted either using two tunnels and a lateral femoral incision or with a femoral half tunnel drilled from the joint, thus avoiding the lateral incision. Advantages of the single-incision technique in the early rehabilitation period have been claimed. 40 patients with ACL deficiency were included in a prospective randomized trial comparing single and two-incision technique with a follow-up period of 4 years. Preoperative data did not show any significant difference between the two groups. At follow-up no difference were observed with respect to complications or he progress of rehabilitation. Evaluation after 1 and 4 years according to the IKDC form revealed good to excellent results in 70% of all patients. The Tegner-score increased significantly, however most patients did not regain their former activity level. ACL-reconstruction reduced anterior translation of the knee significantly at 6 months follow-up. However, we observed a slight increase of anterior translation after 1 and 4 years in both groups; stability was comparable in both groups at all time periods. We conclude that an arthroscopic single-incision technique has no advantage compared to a mini-open two-incision technique for ACL reconstruction with patellar tendon graft in terms of subjective or objective parameters.