In this population-based retrospective cohort study, the 138 Olmsted County, Minnesota residents first diagnosed with Parkinson's disease during 1967-79 were matched by age and sex to an equal number of control subjects from the community. Fractures were assessed through review of each subject's complete (inpatient and outpatient) medical records. At the time of diagnosis, County residents with parkinsonism were no more likely to have a history of selected fractures than control subjects (32% in each group). Subsequently, 33% of cases and 20% of controls experienced one or more new fractures during 696 person-years of follow-up (p = 0.008). The greatest increase in risk was seen for proximal femur fractures, confirming previous case-control studies. By 10 years after diagnosis, an estimated 27% of the parkinsonism cohort had experienced a new hip fracture. The pattern of fractures that was observed suggested that the increased risk was due more to specific types of falls than to disuse osteoporosis.