Many youth are involved in organized physical activity (PA); however, the impact of these activities on daily PA, body fat, and cardiovascular disease (CVD) risk factors is not well understood. Purpose: To compare the overall daily PA and CVD risk factors of girls who participate in organized activities to non-participants throughout adolescence. Methods: Data from the National Heart, Lung, and Blood Institute Growth and Health Study, a 10-year observational study of Black and White girls (N=2379), were analyzed. Organized PA was defined as participation in classes/lessons and sports (0, <4, 4-19.99, ≥20 MET times/wk). Outcomes included daily PA (3-day diary), body fat (bioelectrical impedance analysis), lipids, glucose, insulin, and blood pressure. Longitudinal data were examined for each outcome using a mixed model with repeated measures. Girls were also categorized by the number of years they reported ≥4 MET times/wk of organized PA. Outcomes and risk clustering at 18-19y were evaluated with ANOVA and logistic regression, respectively, by number of participation years. Results: Organized PA and participationtimerace were related to change in daily PA and body fat (p < 0.0001). Although daily PA declined for Black girls, those with ≥20 MET times/wk had higher PA levels than all other girls (p < 0.0001). Change differed by sports participation in White girls (p=0.019); those involved ≥20 MET times/wk demonstrated better maintenance of daily PA. Black girls with ≥20 MET times/wk had significantly lower body fat than non-participants (p=0.002).White non-participants had higher body fat than those with 4-19.99 MET times/wk (p=0.006). Accumulated organized PA was related to daily PA and body fat at 18-19y. Girls who never reported participation had significantly lower daily PA at 18-19y than all other groups (p < 0.02), and significantly higher body fat at 18-19y compared to girls who reported 4y of sports participation (p=0.038). Organized PA was not related to change in other CVD risk factors or risk factor clustering at 18-19y (OR=1.05, 95% CI=0.87-1.27, p=0.59). Conclusion: Organized PA was related to daily PA and body fat for Black and White girls throughout adolescence. Appealing options should be made available and participation encouraged.