This cross-sectional population survey was undertaken to determine the prevalence of type 2 diabetes and impaired glucose tolerance in subjects aged 40 years or more in Kashmir Valley, India. The study was carried out in two phases. In phase one, 6091 randomly selected subjects, 40 years or older, from all six districts of the valley were surveyed for prevalence of known diabetes mellitus. In phase two, 5083 subjects, 40 years or older, were screened with oral glucose tolerance test for prevalence of undiagnosed (asymptomatic) diabetes mellitus and impaired glucose tolerance. Abnormalities of carbohydrate intolerance were determined as recommended by WHO. Of 6091 subjects interviewed, 115 were known cases of diabetes mellitus with an overall prevalence of 1.89% (1.98% in males and 1.77% in females). Results of glucose tolerance test revealed that mean fasting as well as mean 2 h blood glucose was significantly more in females as compared to males (4.68+/-0.91 and 6.40+/-2.12 vs. 4.49+/-0.96 and 5.94+/-2.03 mmol/l, respectively, P < 0.0001). Of 5083 subjects who were subjected to glucose tolerance test (GTT), 627 (12.34%) had an abnormal test; with 411 (8.09%) having impaired glucose tolerance (IGT) and 216 (4.25%) having diabetes mellitus. The prevalence of IGT as well as of diabetes was significantly more in females as compared to males (P < 0.001). Subjects who had family history of diabetes had a significantly higher prevalence of abnormal GTT. Prevalence of known diabetes as well as that of abnormal GTT steadily increased with age, with a highest prevalence in the age group of > or = 70 years (P < 0.001). Obese subjects had a significantly higher basal as well as 2 h blood glucose in males as well as in females. Subjects with diabetes on GTT had a higher waist/hip ratio. Overall the prevalence of diabetes as well as IGT was significantly higher in the urban population. We conclude that 1.89% of the general population have known diabetes, 4.25% have undiagnosed diabetes and 8.09% have impaired glucose tolerance test; making the total load of abnormal glucose tolerance 14.23% in Kashmir Valley. In subjects greater than 40 years of age having a family history of diabetes, obesity, higher age (50 years or above), female sex, and urban origin have more chance (odds ratio: 4.65, 2.30, 1.87, 1.49 and 1.16, respectively) of developing abnormal glucose tolerance.