Objectives Understanding correlates of physical activity and sedentary behaviors may contribute to fostering active lifestyles. This study aimed to identify correlates of physical activity and sedentary behaviors in leisure‐time among Portuguese urban children, during school days. Methods A cross‐sectional survey was conducted with 802 students (416 boys), aged 10–12 years. A questionnaire was used to collect data of physical activity, sedentary behaviors, psychological and behavioral variables related to physical activity and sedentary behaviors. Analyses were run separately for boys and girls. Results Television viewing occupied the most leisure‐time of boys and girls, followed by computer usage, and video game playing. These behaviors occupied 259.7 min/day for boys and 208.6 for girls (P = 0.002). Reported moderate‐to‐vigorous physical activity was 23.7 min for boys and 12.8 min for girls (P < 0.001). Perception of competence and academic achievement were related to physical activity for the boys and girls. Computer use and playing video games with friends were only related to physical activity for the boys. On the other hand, parents' physical activity participation was related with boys' and girls' physical activity. The correlates of sedentary behavior were outdoor play for the boys, age for the girls, and playing video games with friends for both. Conclusions This finding suggests that interventions should be considered to replace joint video game time with joint physical activity time. Am. J. Hum. Biol. 26:407–412, 2014. © 2014 Wiley Periodicals, Inc.