The prevalence of diabetes was determined in a community health survey in the Kiryat Hayovel neighborhood of west Jerusalem. The prevalence rates of diabetes among 4,938 people aged greater than or equal to 15 years were 5.8% in men and 4.6% in women, with a male/female age-adjusted ratio of 1.15. One-third of the diabetics were first diagnosed in this study. In both sexes, the rates increased steeply with age. A higher prevalence rate of diabetes was found in Jews of North African origin, especially in men, than in the other ethnic origin groups. These ethnic differences in men do not appear to be explained by differences in body mass.