A door-to-door survey was carried out in rural areas of the Cordillera Province, Bolivia, to determine the prevalence of Parkinson's diseases (PD) in a sample of 9955 subjects. We found five cases of PD on prevalence day, November 1, 1994. The crude prevalence was 50.2/100,000 (95% CI 18.5-124.5) and 286/100,000 (95% CI 28-543) in subjects aged 40 years or more. Our prevalence is close to rates found in other in developing countries.