To estimate during which period of time the degree of diabetes control is integrated by the level of glycosylated hemoglobin two approachs were used. Hb-g was assayed by cellulose acetate electrophoresis in insulin-dependent diabetics and compared to the degree of control over a 3 months period. Control was evaluated by the semiquantitative urine test for sugar "Clinitest" three time a day. Hb-g correlated highly with last month glycosuria, but not as well with those of the two preceding months. These later correlation in fact reflected the stability of control over the three months. In 7 incipient insulin dependent diabetics in whom normal glycaemia was achieved abruptly and maintained for more than one month, Hb-g fell to normal within one month and therefore did not reflect the prexisting hyperglycemia. Hb-g integrates precisely the degree of diabetes control, but over a one month period only.