Recent studies have found higher rates of failed reconstruction of the anterior cruciate ligament (ACL) with use of allograft when compared with autograft reconstruction. To evaluate the long-term outcomes of allograft ACL reconstruction, we retrospectively reviewed the cases of all patients who underwent allograft (n=99) or autograft (n=24) ACL reconstruction by 2 senior surgeons at a single institution over an 8-year period. Seventeen (17%) of the 99 allograft reconstructions required additional surgery. Reoperation and revision ACL reconstruction rates (30.8% and 20.5%, respectively) were much higher for patients 25 years of age or younger than for patients older than 25 years. In our cohort of NCAA (National Collegiate Athletic Association) Division I athletes, the revision ACL reconstruction rate was 62% for allograft ACL reconstruction and 0% for autograft reconstruction. Our study found that reoperation and revision rates for irradiated soft-tissue allograft ACL reconstruction were higher than generally quoted for autograft reconstruction. Given the extremely high graft failure rates in patients younger than 25 years, we recommend against routine use of irradiated soft-tissue allograft for ACL reconstruction in younger patients.