The Pima Indians of Arizona have the highest recorded prevalence and incidence of non-insulin-dependent diabetes of any geographically-defined population. In this review the prevalence, incidence, risk factors and pathogenesis of diabetes in the Pima Indians are discussed. The epidemiological evidence indicates that non-insulin-dependent diabetes results from interaction of genetic and environmental factors. The principal goal of epidemiological research in diabetes is prevention or postponement of the onset of the disease. Further expansion of the knowledge of genetics of the disease to allow identification of susceptible subjects has important implications for intervention strategies. These may be tested in populations known to be susceptible to the disease and therefore more likely to benefit. Based on the current knowledge of the epidemiology and risk factors for the disease, intervention approaches involving drugs, diet and exercise appear to have the potential to reduce the incidence of diabetes in subjects at high risk.