A door-to-door survey was carried out to screen a community of 14010 people (Parsis living in colonies in Bombay, India) for possible neurologic diseases. High school graduates, social workers, and medical students administered a screening questionnaire that had been shown in a pilot survey to have a sensitivity of 100% for identifying those with Parkinson's disease. Neurologists used defined diagnostic criteria to evaluate individuals positive on the screening survey. There were 46 people (25 men, 21 women) who suffered from Parkinson's disease (328.3 cases per 1000 population). The age-specific prevalence ratios increased consistently with age. Age-adjusted prevalence ratios were slightly higher for men.