Glycosylated hemoglobin A(1c) was measured in 43 insulin-dependent diabetic children before and after training in blood glucose testing. These measurements were compared with those obtained from a group of matched controls who tested urine sugars for the same period. Mean HbA(1c) measurements for the blood glucose testing group were significantly improved at 6 mo after training in blood glucose testing, and were significantly lower than those measured in the urine sugar testing group. However, HbA(1c) levels in the blood glucose testing group were well above levels for nondiabetic persons, and were generally higher than those reported for adult insulin-dependent diabetic persons following training in blood glucose testing. Explanations for this difference were considered. It was noted that 81% of the trained children accepted and continued to use blood glucose testing for at least 9 mo after training.