A large biracial cross-section of 1038 healthy children aged 6-18 yr with 519 blacks, 519 whites, 678 males, and 360 females was evaluated for Tanner stage and serum levels of androstenedione, dehydroepiandrosterone-sulfate, estradiol, progesterone, and testosterone. The anthropometric values of the blacks and whites were very similar at each Tanner stage with only minor differences in age, height, and weight related to an earlier onset of puberty in blacks. The hormones dehydroepiandrosterone-sulfate, progesterone, and testosterone did not exhibit any racial differences. Estradiol showed a significantly higher level among black males compared to white males (P less than or equal to 0.05) whereas androstenedione was significantly higher in both white males (P = 0.0001) and females (P less than or equal to 0.01) compared with blacks. Many hormones are known to effect insulin resistance and others have reported a correlation between insulin levels and androstenedione. Blacks suffer disproportionately from diabetes. Since puberty is a time of dramatic changes in insulin resistance, racial (black-white) differences in steroid hormone changes were explored. This study shows that a racial difference in androstenedione levels exist during puberty, at a time when racial differences in insulin resistance are becoming manifest.