Successful strategies for preventing childhood injuries require better understanding of injury epidemiology. A case-control study was designed to identify risk factors for injury among preschool patients of a university-affiliated, community-based family practice center. Thirty-four children who were injured during a 1-year period and 36 age- and sex-matched controls were included. A description of the injury incident and data from each child's medical record and a parent interview were recorded. All injuries were relatively minor. The following were associated with increased injury risk: a history of a chronic medical condition; weight in the lowest 25th percentile of the national distribution; birth order of third or later in the family; maternal education higher than the high school level; and, possibly, a history of previous injury.