To evaluate the possible interest of the dosage of glycated plasma proteins in the diagnosis of glucidic intolerance, OGTT with determination of glycaemia and insulinaemia, HbA1c and fructosamine was determined in 6 normal and 35 obese subjects. On the basis of OGTT the subjects were subdivided into 20 obese with normal glucose tolerance, 7 with IGT and 8 with DM. In the comparison between all the subjects there was a significantly higher plasma fructosamine concentration in the obese with DM (p less than 0.001). No difference was noticed between the normal subjects and the other two classes of obese patients. This suggests that the evaluation of glycated plasma proteins is scarcely sure in a screening plan.