Prevalence of glucose intolerance and other noncommunicable diseases has been examined in subjects aged 35 years and over in semirural and urban communities in the Fergana Valley in the eastern part of Uzbekistan, Central Asia. Diabetes and impaired glucose tolerance (IGT) were diagnosed according to the recommendations of the latest WHO Study Group on diabetes. Crude prevalence of diabetes was 9% and 5%, respectively, in semirural men and women, 13% and 9% in urban men and women. Crude prevalence of impaired glucose tolerance (IGT) was 6% and 9%, respectively, in semirural men and women, 9% and 8% in urban men and women. After adjustment for non-response, prevalence of diabetes was 5% and 4%, respectively, in semirural men and women and 8% in both urban men and women. Adjusted prevalence of IGT was 4% and 8%, respectively, in semirural men and women, 5% and 6% in urban men and women. The majority of subjects with a prior diagnosis of diabetes were being treated with oral hypoglycaemic agents. Almost one-half of subjects in both communities had body mass index of 25 kg m(-2) or greater. Central obesity (waist-hip ratio 0.95 or greater for men, 0.85 or greater for women) was observed in over one-quarter of subjects in both communities. Clinical hypertension was not frequent by international standards (9% in semirural subjects and 13% in urban subjects) but a number of subjects who were clinically normotensive claimed to be taking antihypertensive medication. It is concluded that glucose intolerance and central obesity are common in this region of Uzbekistan, about which there was previously little information.