Although self-monitoring of blood glucose (SMBG) is an integral part of the daily self-care regimen for the effective management of insulin-dependent diabetes mellitus (IDDM), compliance with this task remains a significant problem, particularly for adolescents. Research should be focused on identifying other management approaches which may supplement SMBG. One potential approach involves placing greater reliance on the patient's own ability to estimate glucose levels. Although some research has examined blood glucose self-estimation in adults, little is known about this construct in children and adolescents. The purpose of the current study was to examine the accuracy of blood glucose self-estimates in adolescents with IDDM and examine the relation between child characteristics and accuracy. The results for 70 adolescents with IDDM indicated that as a group they were moderately accurate in estimating their glucose levels; however, much variability in accuracy was found among subjects. Subject characteristics were not found to be significantly related to accuracy.