PURPOSE: To analyze failure rate in 2-year increments to determine if graft choice changed over time and graft failure rate. METHODS: A prospective 2002-2008 database was used to identify risk factors for anterior cruciate ligament (ACL) retear. Subjects who had primary ACL retear with no history of contralateral surgery and 2-year follow-up were included. Subjects who underwent a multiligament reconstruction were excluded. Graft type, age, sex, smoking status, body mass index, Marx activity level at index surgery, medial and lateral meniscus status at time of ACL retear, sport played after ACL reconstruction, and clinical site were evaluated. Analysis was repeated using 2002-2003 (early) and 2007-2008 (late) 2-year databases. Analysis of variance with post hoc analysis was performed to detect significant differences in age and Marx score by graft type over time. RESULTS: Two-year follow-up for graft failure was obtained on 2,497 of 2,692 (93%) subjects. There were 112 of 2,497 (4.5%) ACL retears identified at 2-year follow-up. The only predictor that changed between early/late periods was allograft use. Allograft odds ratio decreased from 13.1 to 9.5 (P < .01). Allografts were used in older patients (31-40 years) and with lower Marx scores (10-8) from early to late periods. The mean age of subjects who received bone-patellar tendon-bone autografts did not significantly change over time (22.8-23.5). The mean age of subjects who received hamstring autografts fell (27.9-25.5). The mean age of subjects who received allografts rose significantly (31.3-39.8, P < .01). The mean Marx score of subjects who received bone-patellar tendon-bone and hamstring autografts did not significantly change over time. The mean Marx score of subjects who received allografts decreased significantly (P < .01). CONCLUSIONS: After early recognition, allograft use in young active patients was a risk factor for retear; graft choice by surgeons changed in the late period to use of allografts in older and less-active patients, which correlated with a significant decrease in retear risk. LEVEL OF EVIDENCE: Level III, case control study.