Abstract. In a diabetes detection survey based on postprandial Clinistixr̀ testing, 2477 out of 228,833 participants (1.08%) reacted positively. In 2180 a 3‐hour oral glucose tolerance test was performed. Diagnostic criteria for diabetes were established in a random sample from the same population matched in age and sex. The controls were healthy and had no known heredity for diabetes. The requirement for a diagnosis of diabetes was that all 10 capillary blood sugar values during the tolerance test should exceed the corresponding mean plus 3 S.D. for the control group. Likewise a normal tolerance was only considered present when none of the 10 values reached the mean plus 2 S.D. for the control group.A diagnosis of diabetes was made in 538 subjects, i.e. 0.2% of the population under study.Fasting SILA values in 16 normal men less than 50 years of age showed a mean of 94 μU per ml. and in 12 men more than 50 a mean value of 83 μU per ml was found. Fasting SILA values in eight normal women less than 50 showed a mean of 34 μU per ml, and in nine women more than 50 a mean of 75 μU per ml was found. The low value in women less than 50 was significantly different (p <0.001) from the male group and also from values found in women more than 50 years of age (p<0.01).Fasting SILA in 16 men and 14 women with newly discovered diabetes and age more than 50 showed all values in the normal range. Three diabetic women less than 50 had 50, 61, and 146 μU per ml.SILA during the glucose tolerance test in six patients with diabetes showed a subnormal response in all of them.SILA during the glucose tolerance test in five subjects considered diabetics by conventional criteria, but not according to our criteria, showed a normal response.Fasting serum corticosteroids in six diabetic subjects were significantly higher than in five controls.Serum corticosteroids during the glucose tolerance test dropped to the same base level both in the diabetic and in the normal group.