This study examined screen media time usage (SMTU) and its association with personal and socioeconomic factors, as well as the effect of season and type of day, in a Spanish sample of 12-16 year-old school adolescents (N=323). The research design was a cross-sectional survey, in which an interviewer-administered recall questionnaire was used. Statistical analyses included repeated measures analyses of variance, analysis of covariance and structural equation models. Results showed an average of 2.52h per day of total SMTU and partial times of 1.73h per day in TV viewing, 0.27h per day in computer/videogames, and 0.52h per day in mobile use. Four significant predictors of SMTU emerged. Firstly, the type of school was associated with the three media of our study, particularly students from state/public school spent more time on them than their private schools counterparts. Secondly, older adolescents (14-16 years old) were more likely to use computer/videogame and mobile phone than younger adolescents. Thirdly, the more accessibility to household technology the more probable computer/videogames and mobile phone were used. Finally, boys spent significantly more time in mobile phone than girls. Additionally, results revealed that adolescents seemed to consume more TV and computer/videogames in autumn than in winter, and more TV and mobile phones on weekends than on weekdays, especially among state school students. Findings from this study contribute to the existing knowledge on adolescents' SMTU patterns that can be transferred to families and policies.