Type 2 diabetes mellitus is a chronic disease which causes neurologic, cardiac, vascular, ocular and renal complications. The present study documented the prevalence of diabetes and associated risk factors in 1774 adults who were older than 30 years. An oral glucose tolerance test (OGTT) was conducted according to the World Health Organization (WHO) criteria. Of the 1452 subjects, 58 (4%) had diagnosed diabetes, 41 (2.9%) undiagnosed diabetes and 130 (9%) had impaired glucose tolerance. The total glucose intolerance was 15.9%. The prevalences of type 2 diabetes mellitus (9.7%-4.1%) were significantly different in low occupational and high occupational activity groups, respectively (P<0.0001). The prevalence of type 2 diabetes mellitus was 17.9% among the hypertensive group (P<0.0001). The prevalence of type 2 diabetes mellitus was higher in smokers (P<0.05). Patients with diagnosed diabetes, undiagnosed diabetes and IGT were older, more obese and have higher blood glucose values, triglyceride values, systolic and diastolic blood pressures than healthy subjects (P<0.001). We conclude that type 2 diabetes mellitus and IGT prevalences are quite high in the urban area of Kayseri, central Anatolia and multivariate analysis indicated that low occupational activity, low leisure activity, family history for diabetes, hypertension and obesity were significant independent risk factors for diabetes mellitus.