Little epidemiological data are available on the dependency status of elderly patients with Parkinson's disease (PD) living in the community. This study assessed the activities of daily living (ADL), the instrumental activities of daily living (IADL), and mobility in a representative sample of elderly nondemented PD subjects (n = 20), compared to a control population (n = 2,697). We found a significantly higher level of dependency in the PD sample based on ADL, IADL, and mobility scales. Half of the PD subjects were dependent for ADL (versus 13.2% for controls), 80% were dependent for IADL (versus 28% for controls), and 20% had their mobility restricted to their home (versus 1.5% for controls). The proportion of PD patients tended to be higher in those more depressed or with more severe motor symptoms. PD patients were not found to be more isolated socially or from family than was the control group and, in any case, dependency seemed not to be associated with isolation. When adjusting for age, sex, depressive symptoms, Mini Mental Status examination score, and dyspnea, PD remained significantly associated with dependency. PD thus constitutes a significant factor of dependency in elderly subjects living at home. Institutionalization occurred over four times more frequently in the PD group than in the general population, but no specific factor of institutionalization was noted.