Objectives: To compare the prevalence of television (TV) watching and of computer/videogame use among high school students (15-19 years) from Southern Brazil between 2001 and 2011 and to identify associated socio-demographic factors. Methods: Panel studies were conducted with high school students in the state of Santa Catarina, Brazil, in 2001 (n = 5,028) and 2011 (n = 6,529). TV watching and computer/videogame use were collected using questionnaires. Results: Prevalence of ≥2 h/day of TV watching dropped from 76.8 to 61.5 % and ≥2 h/day of computer/videogame use increased from 37.9 to 60.6 %. In both surveys, those aged 15-16 and those who did not work had higher likelihoods of being exposed to ≥2 h/day of TV watching. Boys, those with higher family income, and those who were living in urban areas had higher likelihoods of ≥2 h/day of computer/videogame use. Older age, studying at night and not working were protective factors to these behaviors. Conclusions: After a decade, there was a decrease in the prevalence of TV viewing and an increase in computer/videogame use. Socio-demographic factors were differently associated with these behaviors.