Peyronie's disease was diagnosed in 101 male residents of Rochester, Minnesota between 1950 and 1984. Mean patient age at diagnosis was 53 years. The average age-adjusted annual incidence rate of 25.7 and a prevalence rate of 388.6 per 100,000 male population were noted. The steady increase in incidence with time may reflect an increasing tendency to obtain medical help. However, the possibility of a true increase in the incidence rate cannot be ruled out. An effort was made to identify possible risk factors and other disease associations. Rheumatoid arthritis and hypertension were more common among the patients compared to the Rochester population. In contrast, no excess of diabetes mellitus was observed among patients with Peyronie's disease.