Over 20% of middle aged and elderly South Asian people throughout the world have diabetes. The associated mortality and morbidity risks are unclear. We compared mortality and morbidity in a cohort of South Asian and European people with diabetes in London, UK, in an 11-year follow-up of a population-based sample of 730 South Asians (mean age 55 in 1984) and 304 Europeans (mean age 67 in 1984) with diabetes aged 30 years and above in 1984. By 1995, 242 (33%) of South Asians, and 172 (57%) of Europeans had died. The all-cause mortality rate ratio (South Asian versus European) was 1.50 (95% CI 0.72-3.12) for those aged 30-54 years at baseline. Ethnic differences in mortality rates were abolished or reversed in people aged 65 years and above at baseline. The mortality rate ratio for circulatory deaths was 1.80 (95% CI 1.03-3.16, p < 0.05) and for heart disease was 2.02 (95% CI 1.04-3.92, p < 0.05) in those aged 30-64 years at baseline. Seventy-seven per cent of South Asian deaths were caused by circulatory disease, compared with 46% of European deaths. South Asian survivors were 3.8 times (95% CI 1.8-8.0, p = 0.001) more likely to report a history of myocardial infarction than Europeans. South Asian adults with diabetes show a markedly increased predisposition to cardiovascular disease compared with Europeans, especially in younger people. This emphasizes the urgent need to reduce cardiovascular risk in this vulnerable group.