There are few reports on the longevity of anterior cruciate ligament (ACL) reconstruction in adolescents. In the study reported here, we performed a survivorship analysis of our experience with ACL reconstructions in adolescents. We retrospectively reviewed the cases of 276 consecutive patients (girls’ bone age, >13 years; boys’ bone age, >14 years; chronological age, <18 years) who underwent primary ACL reconstruction. All patients underwent transphyseal ACL reconstruction with Achilles tendon soft-tissue allograft using the same technique. Twenty-nine patients (10.5%) were excluded or lost to follow-up. Mean follow-up of the remaining 247 patients was 6.3 years (range, 2- 10 years). Data were collected from charts and telephone interviews. Failure was defined as the report of symptomatic knee instability and/or revision ACL surgery. The Kaplan-Meier method showed that 1-year survivorship of ACL reconstruction was 96.4% and 5-year survivorship was 93.1%.