The purpose of this study was to compare the single-incision, "endoscopic" (ENDO) anterior cruciate ligament (ACL) reconstruction technique with the two-incision, "rear-entry" technique (RE). Sixty patients were entered into a prospective study. Thirty patients underwent ACL reconstruction by the RE technique, followed by 30 consecutive patients using the ENDO procedure. Postoperatively all patients followed a standardized rehabilitation protocol. Follow-up evaluation consisted of a detailed physical examination, range of motion, thigh girth, vertical leap, hop test, KT-1000 testing, and patient interview. They were scored according to the International Knee Documentation Committee (IKDC) protocol, which takes objective and subjective data into account. Patients were also assessed for level of sports activity including frequency and type. Finally, anteroposterior and lateral x-ray films were evaluated with a scoring system for tunnel location. Of the initial 60 patients entered into the study, 50 were available for a detailed clinical and functional review (83%). Demographic comparisons revealed 24 RE patients and 26 ENDO patients. There were 16 men and 8 women in the RE group. The ENDO group comprised 16 men and 10 women. There were 14 right knees and 10 left knees in the RE group. In the ENDO group there were 13 right knees and 13 left knees. The average age in the RE group was 24 years and 25 years in the ENDO group. The average follow-up was 35 months (range 31-40 months) in the RE group and 29 months (range 24-35 months) in the ENDO group. Complications included two patients with loss of motion in the RE group and three in the ENDO group. There were no significant differences between the two groups tested with respect to the overall IKDC rating scale. Anteroposterior and lateral x-ray films revealed no significant differences in femoral and tibial tunnel placement. In conclusion, no significant functional or radiographic differences at a minimum 2-year follow-up could be identified when comparing the two ACL reconstructive techniques.