A national survey of glucose intolerance and cardiovascular disease risk factors in Oman has demonstrated a high prevalence of diabetes (10%) and impaired glucose tolerance (IGT, 13% in females and 8% in males). Prevalence of diabetes rose with age to a maximum of over 30% in both sexes. Prevalence of total glucose intolerance (diabetes and IGT combined) exceeded 50% in the seventh (females) and eighth (males) decade of life.