Anterior cruciate ligament (ACL) reconstruction is one of the most frequently performed orthopaedic procedures. Failures are a reality of surgery; to limit failures, we must first understand and quantify them. The purposes of this study were to determine the rate and factors associated with graft failure after anatomic ACL reconstruction performed with allograft. Case series; Level of evidence, 4. All consecutive subjects who underwent anatomic single- or double-bundle ACL reconstruction with allograft between January 2007 and December 2009 were included and followed clinically. Graft failure was defined as patient-reported instability, pathological laxity during the physical examination, or evidence of a failed graft on magnetic resonance imaging or during arthroscopy. Potential predictors of graft failure that were explored included subject age, sex, height, weight, body mass index, meniscus injury, and time of return to preinjury sports. There were 206 subjects included in this study: 168 double-bundle and 38 single-bundle reconstructions. Overall, 27 (13%) subjects experienced graft failure. Twenty-three (13%) double-bundle subjects failed. The characteristics associated with double-bundle graft failure were younger age (19 vs 25 years, P < .001) and earlier return to sports (at 222 vs 267 days, P = .007). Four (11%) of the single-bundle subjects failed. The characteristics associated with single-bundle graft failure were younger age (19 vs 24 years, P = .049) and increased body mass (83 vs 65 kg, P = .031). The overall graft failure rate after anatomic ACL reconstruction with allograft was 13%. Younger age, earlier return to sports, and a higher body weight were associated with graft failure.