Objective To determine the prevalence of diabetes and IGT and their risk factors in the population of China. Research Design and Methods This study was a population-based, cross-sectional study of 224,251 residents aged 25 years and over in 19 provinces and areas, including cities and rural areas of the north, the south, the east and middle part of China. Results 1. Using 1985 WHO criteria the prevalence of diabetes and impaired glucose tolerance (IGT) were 2.5% and 3.2% respectively in 213,515 subjects aged 25 to 64 years. 2. Two thirds (70.3%) of the cases had newly recognised diabetes. 3. The prevalence of diabetes in China is about 3 times higher than it was ten years ago, and the rate is increasing faster in the countryside than in cities. 4. Multiple logistic, stepwise regression analysis shows that age, BMI (or WHR), family history of diabetes, hypertension, less physical activity and higher annual income are independent risk factors of NIDDM, and that low education is also an independent risk factor of NIDDM in people with higher personal annual income.