The aim of the study was to describe the associations between socio-economic status and type 2 diabetes in a non-institutionalised population aged 70 years or over. Diabetes was assessed on the basis of self-reports and additionally 2-h oral glucose tolerance test for the subjects on diet treatment. Socio-economic status was assessed by questions on marital status, number of residents in household, basic education, self-rated income and economic status. In the population of 379 subjects (141 men), 14% (n = 19) of men and 19% (n = 46) of women had known diabetes. Known diabetes was less common among married compared to unmarried, widowed or divorced subjects. Diabetes was also more common among men with higher compared to lower level of basic education, while a reverse trend was seen among women. Women, who had been engaged in manual labour, had diabetes more often compared to those engaged in administrative work. Diabetes was more common among men who rated their income as good, but the opposite was true of women. Higher income among men and lower income among women were the most powerful variables associated with known diabetes. Known diabetes was more common in elderly women with lower socio-economic status, whereas the opposite was true of men. This finding suggests that the impact of the socio-economic changes that have taken place in Finland in the 20th century on the risk factors for diabetes has been greater among men with higher and women with lower socio-economic status.