This is a 2-year prospective observational study of fractures occurring in residents of a live in center for developmentally disabled adults that is designed to identify risk factors that predispose to injury in this group. Fifty-eight individuals sustained 67 fractures during the study period. Only 18 of the 67 (27%) fractures were witnessed by the healthcare staff. Most fractures were diagnosed by subtle findings of erythema or swelling or by a change in the patient's behavior. Thirty-three of 332 (10%) community ambulators compared with 25 of 103 (24%) less functional residents incurred fractures. This difference is highly significant. Thirty-one of the 58 (53%) patients who sustained fractures during the study had a history of fracture before the study period. Thus, programs to reduce fractures should focus on residents with previous fractures and those with more severe disabilities.