Objective: This study evaluated racial differences in the metabolic control of children and adolescents with insulin-dependent (type I) diabetes mellitus and examined the interactive effects of race with age and sex. Research Design and Methods: Data on several demographic and clinical variables were obtained for 102 black and 108 white children, including the percentage of total HbA1, age, age at diagnosis, duration of diabetes, pubertal status, insulin dose (U · kg−1 · day−1), body mass index, number of clinic visits kept and missed, number of hospitalizations for diabetic ketoacidosis (DKA) for the year, and socioeconomic status (SES). Results: Black children had higher insulin dosages (P < 0.05) and lower SESs (P < 0.001) than white children. HbA1 was higher in black than white children (P < 0.01) after statistically adjusting for the effects of insulin dose, diabetes duration, and SES. With HbA1-based criteria, more black than white children were in poor and fewer in good metabolic control (P < 0.001). Older children (≥ to 13 yr) had higher HbA1 levels than younger (< 13 yr) children (P < 0.002), but there were no differences in HbA1 between males and females nor were there interactive effects of race, sex, and age-group. Black children were hospitalized for DKA more frequently than white children (P < 0.04). More black than white children missed clinic visits (P < 0.01), but they did not differ in number of visits kept. Conclusions: Black youths with type I diabetes mellitus are in poorer metabolic control than white youths.