Major sociodemographic changes have occurred in Egypt to promote the development of noncommunicable diseases. We have performed a cross-sectional, population-based survey of persons > or = 20 years of age in Cairo and surrounding rural villages to describe the prevalence of diabetes risk factors, diagnosed diabetes, previously undiagnosed diabetes, and impaired glucose tolerance by age, sex, rural and urban residence, and socioeconomic status (SES). In the survey, we identified 6052 eligible households: 76% of household respondents completed a household examination and 72% of selected household respondents subsequently completed a medical examination. Exercise was assessed by questionnaire; adiposity by measurement of height, weight, and girths; and diabetes by history and 2-h 75 g oral glucose tolerance test. In rural areas, 52% of persons > or = 20 years of age were sedentary, 16% were obese, and 4.9% had diabetes. In lower SES urban areas, 73% were sedentary, 37% were obese, and 13.5% had diabetes. In higher SES urban areas, 89% were sedentary, 49% were obese, and 20% had diabetes. The combined prevalence of diagnosed and undiagnosed diabetes in the Egyptian population > or = 20 years of age was estimated to be 9.3%. Approximately half the diabetes was diagnosed and the other half was previously undiagnosed. The prevalence of diabetes in Egypt is high, and the gradient in risk factors and disease from rural to urban areas and in urban areas from lower to higher SES suggest that diabetes is a major, emerging clinical and public health problem in Egypt.