Objectives To examine the independent associations between television, computer, and video game use with physical violence in youth. Methods The study population consisted of a representative cross-sectional sample of 9,672 Canadian youth in grades 6-10 and a 1-year longitudinal sample of 1,861 youth in grades 9-10. The number of weekly hours watching television, playing video games, and using a computer was determined. Violence was defined as engagement in >= 2 physical fights in the previous year and/or perpetration of >= 2-3 monthly episodes of physical bullying. Logistic regression was used to examine associations. Results In the cross-sectional sample, computer use was associated with violence independent of television and video game use. Video game use was associated with violence in girls but not boys. Television use was not associated with violence after controlling for the other screen time measures. In the longitudinal sample, video game use was a significant predictor of violence after controlling for the other screen time measures. Conclusions Computer and video game use were the screen time measures most strongly related to violence in this large sample of youth.