Numerous studies have compared patellar tendon (PT) and hamstring tendon (HS) anterior cruciate ligament (ACL) reconstructions in the short to midterm, but fewer long-term results have been published.There will be no difference in functional outcome between ACL reconstruction performed with PT and HS grafts, but PT grafts will have more donor site morbidity.Randomized controlled trial; Level of evidence, 1.Sixty-five patients undergoing ACL reconstruction were randomized to receive either a PT graft or a 4-strand HS graft. Early results were reported at 4, 8, 12, 24, and 36 months. Forty-seven patients (22 of 31 PT and 25 of 34 HS) were reviewed at a mean of 15.3 years.Four graft ruptures (1 PT, 3 HS) and 6 contralateral ACL injuries (4 PT, 2 HS) occurred in the group that was reviewed. There was no statistically significant difference between the groups for any of the variables measured. There was a similar incidence of anterior knee pain and kneeling pain in both groups. The previously observed increased extension deficit in the PT group at 3 years was not present at 15 years, and there was no significant between-group difference in knee laxity. A higher proportion of patients in the PT group were participating in sport on a weekly basis (73% PT, 48% HS; P = .05). There was no difference in the degree of osteoarthritis between the groups.This randomized controlled trial showed that HS and PT ACL reconstructions have comparable results at an average 15-year follow-up. Contrary to the study hypothesis, some of the graft differences seen at earlier review were not present at 15 years, and patients with PT grafts were more active in sport participation. Overall, both graft types provided good long-term subjective and objective outcomes.