Blood glucose at fasting and 1, 2, and 3 hours after meals GHb (glycosylated hemoglobin) were determined in 66 subjects. Based on WHO criterion, 34 of them were diabetics, and 32 were nondiabetics, in whom impairing of glucose tolerance (IGT) and diabetes were ruled out. The results showed that the concentrations of blood glucose, at fasting, and 1, 2, and 3 hours after meals, blood glucose area, and GHb in diabetic patients were significantly higher than those in the controls. There was a significant positive correlation between GHb and blood glucose at fasting and 2 hours after meal, and between GHb and blood glucose area in all subjects. Relative sensitivity of GHb for detecting diabetes mellitus was 88%, and relative specificity was 93.75%.