A cross-sectional study of the prevalence and distribution of diabetes among 40- to 69-year olds in Galicia (NW Spain) is presented. A (R)Reflotron system was used to measure the capillary fasting glucaemia in 1275 subjects randomly chosen from the electoral roll, who also answered a short questionnaire and were weighed and measured. The prevalence of diabetes was 7.5% regardless of sex or habitat (urban or rural), and increased significantly with age. These data are in keeping with the scant available information from other parts of Spain and the world in general. The lack of difference between urban and rural habitats was unexpected in view of previously reported dietary differences between both areas.