ChildrenAbstractObjective: To describe the association between electronic devices in the bedroom with seden-tary time and physical activity, both assessed by accelerometry, in addition to body mass indexin children from São Caetano do Sul.Methods: The sample consisted of 441 children. The presence of electronic equipment (televi-sion, personal computer, and videogames) in the bedroom was assessed by a questionnaire. Forseven consecutive days, children used an accelerometer to objectively monitor the sedentarytime and moderate-to-vigorous physical activity. Body mass index was categorized as suggestedby the World Health Organization.Results: Overall, 73.9%, 54.2% and 42.8% of children had TV, computer, and videogames in thebedroom, respectively, and spent an average of 500.7 and 59.1 min/day of sedentary time andmoderate-to-vigorous physical activity. Of the children, 45.3% were overweight/obese. Girlswith a computer in the bedroom (45 min/day) performed less moderate-to-vigorous physicalactivity than those without it (51.4 min/day). Similar results were observed for body mass indexin boys. Moderate-to-vigorous physical activity was higher and body mass index was lower inchildren that had no electronic equipment in the bedroom. Presence of a computer (ˇ = −4.798)and the combination TV + computer (ˇ = −3.233) were negatively associated with moderate-to-vigorous physical activity. Videogames and the combinations with two or three electronicdevices were positively associated with body mass index. Sedentary time was not associatedwith electronic equipment.