Cholesterol levels of serum high-density lipoprotein (HDL) subclasses, HDL2 and HDL3, were examined in a random subsample (n = 561) of children (7 to 17 years of age) from a total biracial community. Overall, black children in younger (7 to 10 years) and older (11 to 17 years) age groups alike had significantly higher HDL2 cholesterol (HDL2-C) and HDL3-C than their white counterparts. In addition, black children had a relatively higher frequency ofjoint occurrence of high levels of both HDL2-C and HDL3-C. A significant sex-related difference, with girls showing higher values than boys, was noted among younger age groups for HDL2-C. A male-female crossover trend in HDL2-C levels was apparent only among white children, with girls showing higher values after age 11. Both age and sexual maturation were inversely associated with HDL3-C levels in white children, irrespective of sex (p < .001). Serum triglycerides were inversely related to both HDL2-C and HDL3-C only in white children (p < .001). A black-white difference in HDL2-C persisted only among boys and girls in the older age group after adjusting for the covariates (sexual maturation, age, adiposity, oral contraceptive use, cigarette smoking, alcohol use, and serum triglycerides). With respect to HDL3-C, the covariateadjusted difference remained significant only among boys in the older age group. Metabolic variations between the races in response to both physiologic and environmental factors likely account for the divergence in antiatherogenic HDL pattern.