BACKGROUND: Anterior cruciate ligament (ACL) tears are thought to occur with increasing frequency in young patients. No study has shown increased incidence over time. We hypothesized the incidence of ACL tears in young patients has increased over the past 20 years. METHODS: This descriptive epidemiology study is a retrospective review of insurance billing data of all patients aged 6 to 18 years with Current Procedural Terminology, Fourth Revision codes for ACL tear and reconstruction or International Classification of Diseases, Ninth Revision, Clinical Modification codes from 1994 to 2013. Injuries were normalized to persons per year enrolled in the insurance database based on age and sex. Analysis was performed based on sex and age (6-14, 15-16, and 17-18 years). RESULTS: The rate of ACL tears per 100 000 person-years averaged 121 +/- 19 (range 92-151). All trends increased significantly except for the male 6- to 14-year-old and 17- to 18-year-old age groups. Overall there was an annual increase of 2.3%. Females had significantly higher incidence except in the 17- to 18-year-olds. Females peaked at age 16 years and males at age 17 years, with rates of 392 ACL tears and 422 ACL tears per 100 000 person-years, respectively. CONCLUSIONS: The incidence of ACL tears in pediatric patients increased over the last 20 years. Females were at higher risk except in the 17- to 18-year -old group. Peak incidence is noted during high school years. These data help target the most at-risk patients for ACL prevention programs.