Limited information is available regarding the relationship between physical activity and blood lipids in black populations. To assess the association, the authors measured high-density lipoprotein cholesterol (HDL-C) and subfractions (HDL(2)-C, HDL(3)-C), physical activity (Harvard Alumni Survey), height, weight, cigarette, alcohol, and oral contraceptive use (questionnaire) in a sample of 173 black freshmen college students at the University of Pittsburgh (59 male, 55 female) and Paine and Augusta colleges in Georgia (14 male, 18 female).Results indicated HDL-C, HDL(2)-C, and HDL(3)-C were significantly higher among women compared with men after adjustment for age, body mass index, alcohol consumption, physical activity, and oral contraceptive use. No significant sex differences were noted for physical activity, however a significantly greater proportion of women reported low physical activity levels (<2000 kcal/wk, 54 percent female, 31 percent male, P < .05). Physical activity was univariately associated with HDL-C (r = .32, P < .01) and HDL(2)-C (r = .29, P < .05) among women. No significant correlations among physical activity and lipid variables were noted among men. The results from stepwise multiple linear regression models (variables included were age, body mass index, physical activity, and oral contraceptive use) revealed that among women physical activity was the only significant independent predictor of both HDL-C and HDL(2)-C explaining 11 and 9 percent of the variance in HDL-C and HDL(2)-C, respectively. Physical activity was not a significant predictor of any of the lipid variables among men.If confirmed, the study finding of a significant association between physical activity and HDL-C and HDL(2)-C among black women suggests that increased physical activity may be an important intervention for the reduction of cardiovascular risk in this high-risk group.