A door-to-door survey was conducted in six cities of the People's Republic of China. A total of 63,195 individuals were sampled during 1983 to determine the prevalence of major neurologic disorders. The survey involved a complete census, followed by a pretested interview and brief screening examination with a high level of sensitivity for detecting individuals with frequently occurring neurologic diseases, including movement disorders. Subjects with abnormal responses or findings were examined by a neurologist. There was 100% cooperation among the study subjects. Twenty-eight individuals alive on prevalence day (Jan 1, 1983) were identified as having Parkinson's disease, yielding an age-adjusted (to the 1960 US population) prevalence ratio of 57 per 100,000 population. All subjects were older than the age of 50 years. After the fifth decade of life, the age-specific prevalence ratios increased with age.