Parkinson''s disease (PD) rates were examined by province and by sex for Canada for the years 1979–1984. As seen with other studies, PD displayed an uneven geographic distribution in the average annual prevalence rates for both males and females. The distribution of prevalence rates indicated a higher prevalence of PD in the western-most provinces. Nationally, males had a statistically significantly higher prevalence than females. Three provinces displayed a statistically significant sex difference with 2 provinces having a higher prevalence rate among males and 1 with a higher prevalence among females. The uneven distribution of prevalence rates offers some support for the involvement of environmental influences in the etiology of P