Background:Standardized measures of energy expenditure (EE) for sedentary activities in youth are needed. The goal was to determine EE of common contemporary and computer-related sedentary activities in youth.Methods:We measured EE for sedentary tasks in 10- to 17-year-old youths (n = 24) during ~24 hours in a whole-room indirect calorimeter. Directly monitored tasks were performed for ~10-min. EE was calculated from oxygen consumed and carbon dioxide produced, converted to metabolic equivalents (MET) by normalization to an individual’s measured resting EE, and compared with the Compendium of Energy Expenditures for Youth.Results:Compared with the youth compendium, measured METs were lower for internet surfing (1.3), computer keyboard typing (1.3), and sorting beads/crafts (1.5) (all P < .002), and similar for handwriting (1.4), playing cards (1.6), video-gaming (1.6), and telephoning (1.5).Conclusions:Current youth compendium MET estimates should be used with caution when predicting EE of common contemporary and computer-related sedentary activities in youth.