• Bicycle crashes are a major cause of injuries in childhood. The goal of this study was to determine the effects of bicycle-related injuries on the subsequent bicycle-riding behavior and safety practices of the child and other family members. Successful telephone contact was made with the parents of 82 of 230 children (age at time of injury, 4 to 15 years; median, 9 years; 57 boys and 25 girls) admitted to the hospital with bicycle-related injuries from 1983 to 1986. Parents were interviewed by telephone 4 months to 6 years after injury (median, 1 year 9 months). Head injuries predominated (64.6%). Almost all children continued to ride a bicycle after hospitalization (80 [97.6%]). Few wore a bicycle helmet either before (6 [7.3%]) or at the time of injury (3 [3.7%]). More began wearing helmets after hospital discharge (20 [24.4%]), but three fourths of the children still rode their bicycles without protective head wear. Helmet wearing also increased among bicycleriding siblings after the index hospitalization (3 [7.0%] of 43 vs 7 [16.3%]) but the difference was not significant. Parents commonly imposed restrictions on bicycle riding before hospitalization (78.0%) and after hospital discharge (82.9%). Twenty-six families (31.7%) reported more stringent rules after injury. Only 17 children (20.7%) participated in formal bicycle safety programs before the injury; only 5 (6.1%) more went through such a program after hospital discharge. Alone, an injury seems to have limited effect on the adoption of safe bicycling practices among children. The hospitalization of injured children provides opportunities for safety education to foster safe bicycling and to prevent injuries of all causes.