In 11 insulin-dependent diabetic outpatients, haemoglobin AIc (HbAIc) was measured by an electrofocusing method. Diabetic control was evaluated by the semiquantitative urine test for sugar, 'Clinitest', three times a day every day in the 8 weeks before the HbAIc determination. 24-hour glycosuria and fasting and postprandial blood-glucose levels were measured one to five times during this period. The HbAIc concentration correlated highly with the semi-quantitative urinary-sugar-concentration index but not with the other parameters.