The prevalence and incidence of type 2 diabetes in Finland was evaluated on the basis of three large population surveys and the national register of diabetics receiving drug therapy. The prevalence of type 2 diabetes was 16 per 1000 in persons aged 30 years and over in a survey conducted in 1966–72,29 per 1000 in a survey conducted in 1976 and 32 in a survey from the years 1979–80. The secular increase in the prevalence rates seemed to be particularly evident in diabetics treated by diet only. According to the drug-recipient register the prevalence of type 2 diabetes is higher in eastern and northern parts of the country. The mean annual incidence of type 2 diabetes estimated on the basis of data from drugrecipient register and the latest of the three population surveys was in Finland in 1970s about 4 per 1000 in pesons aged 30 and over. Key words: Diabetes mellitus, epidemiology