Injuries associated with nonmotorized three-wheeled vehicles were prospectively evaluated through a standard questionnaire during the summer months at the emergency department of the Children's Hospital of Philadelphia, Pa. Forty-four children, including 32 boys, with a mean age of 3.77 years, reported such injuries. Most fell (36.4%), but a second vehicle was often involved. Most children (33 of 44) were on low-slung Big Wheels. Head, neck, and dental injuries accounted for the majority. Most injuries were not serious. Two patients were admitted; both had fractures, one of them had a concussion. Data from the US Consumer Product Safety Commission corroborate the epidemiology of these injuries. Recommendations of safety precautions with non-motorized three-wheeled vehicles are reviewed.