OBJECTIVES To estimate and describe morbidity from sports and recreation injuries in children and adolescents. DESIGN Survey conducted by the National Center for Health Statistics--the Child Health Supplement to the 1988 National Health Interview Survey. SETTING The general community. PARTICIPANTS Representative sample of the noninstitutionalized civilian US population. Five percent of the eligible households did not participate. The subject of this report is 11,840 children and adolescents aged 5 to 17 years. MAIN OUTCOME MEASURES Medically attended nonfatal injuries resulting from sports and recreation, and serious sports injuries, defined as injuries resulting in hospitalization, surgical treatment, missed school, or half a day or more in bed. Sports and recreation injuries were defined as those occurring in a place of recreation or sports, or receiving any of the following International Classification of Diseases, Ninth Revision (ICD-9) E-codes: struck in sports, fall in sports, bicycle-related injury, riding an animal, water sports, overexertion, fall from playground equipment or other vehicles, primarily skates and skateboards. RESULTS The estimated annual number of all injuries from sports and recreation in US children and adolescents is 4,379,000 (95% confidence interval = 3,147,000 to 5,611,000); from serious sport injuries, 1,363,000 (95% confidence interval = 632,000 to 2,095,000). Sports account for 36% of injuries from all causes. Cause and nature of injury are strongly related to age. Sports do not account for a disproportionate number of serious or repeated injuries compared with other causes of injuries. CONCLUSION Sports activities account for a large number and substantial proportion of all injuries to children and youth.