In order to verify the epidemiology of Parkinson's disease in northern-Italy, we carried out a descriptive study in the Local Health Service No. 30 of Cento, Emilia-Romagna. Based on 73 accepted cases, the prevalence rate on December 31, 1987, was 190.3 per 100,000 population. No significant difference was reported between the two sexes. The highest rates were observed in the age groups over 60 years. Our data indicate that the risk of Parkinson's disease in northern-Italy is similar to that observed in other Caucasian populations.