The Childhood Injury Prevention Program of the Boston Department of Health and Hospitals conducted a survey of injury risk in Boston's playgrounds. A standardized checklist was used to assess a 25% sample of public playgrounds for hazards. Climbers accounted for 34% of the hazards observed and had the greatest proportion of significant hazards. The surfacing material in 100% of the playgrounds observed was unsafe. Urban children risk exposure to hazardous playground equipment frequently situated above unsafe surfacing material.