The contribution of organized sport participation to the total daily energy expenditure (TDEE) of youth was estimated in a sample of 90 males and 93 females, 12-14 years of age. TDEE and moderate-to-vigorous energy expenditure (MVEE) were estimated using a 3-day activity record. Males expended 20.4% of TDEE in youth sports; the corresponding estimate for females was 16.3%. Males and females expended 55% and 64.6%, respectively, of MVEE in youth sports. Youth who participated in organized sports had greater TDEE and MVEE, and spent less time watching television than those who did not participate. Thus, organized sport participation appears to be a significant component of daily energy expenditure among youth.