We evaluated the risk factors for nursing home placement of patients with Parkinson's disease (PD) by matching 11 PD patients permanently admitted to nursing homes with two control PD patients remaining at home. Risk factors assessed were motor severity, presence of hallucinations/delusions, and presence of memory of problems. The only statistically significant risk factor was the presence of hallucinations/delusions. Motor severity and the presence of memory problems did not have an impact on nursing home placement. There was no risk factor synergy for hallucinations, motor disability, and mental impairment. Since all patients in this series who entered nursing homes remained there permanently, these data suggest that vigorous efforts to control hallucinations may be warranted to prevent nursing home placement.