Hepatic lipase (HL) is an important determinant of high-density lipoprotein (HDL) concentrations. A common C-to-T substitution at position -514 of the promoter region of the HL gene has been shown to be associated with HL activity and HDL cholesterol (HDL-C) levels. The current study examines the influence of this polymorphism on both levels and serial changes of HDL-C from childhood to adulthood in a community-based sample of 707 white and 291 black unrelated individuals aged 4-38 years using a repeated measures analysis. The frequency of the -514T allele was lower in whites than in blacks (0.228 vs. 0.545, P<0.001). After adjusting for age and BMI, the genotype effect on longitudinal profiles of HDL-C levels was significant (P=0.003) in white males with values in the order of T/T>T/C>C/C. Although a similar trend was seen, the genotype effect was not significant in white females and blacks. Further, the slopes of the age trajectories of HDL-C were similar in three genotype groups in blacks and whites. A sex-genotype interaction effect (P=0.043) on longitudinal profiles of HDL-C levels was found in whites, but not in blacks. White males showed a stronger genotype effect (3.6 mg/dl, P=0.003) than white females (0.5 mg/dl, P=0.601). Thus, the -514T variant of the HL gene is consistently associated with higher levels of HDL-C longitudinally since childhood, but not with rate of change over time. These results suggest that the HL gene may play an important role in the regulation of HDL-C levels from childhood to adulthood, especially in white males.