Objective To investigate the effects of television-watching and computer-using on sleep/wake patterns, sleep duration and sleep problems of school-aged children in Shanghai. Methods A total of 4 108 school-aged children from 10 primary schools of Shanghai were enrolled by multi-stage cluster sampling and surveyed by questionnaires. The information of television-watching and computer-using, family and personal condition was investigated by self-prepared questionnaire, and the Chinese version of Children's Sleep Habits Questionnaire was employed to survey the sleep behaviors of children. The effects of television-watching and computer-using on sleep/wake patterns, sleep duration and sleep problems were analyzed by multiple linear regression analysis and Logistic regression analysis. Results The percentage of children who watched television≥2 h per day was 4.1% during weekdays, and that came to 49.2% during weekends. In terms of frequency of computer-using, most children reported “rarely” (88.2%, 0-1 time/week), followed by “often” (11.0%, 2-4 times/week) and “usually” (0.8%, 5-7 times/week). With the age increase, the percentages of children who watched television≥2 h per day and those who “often” used computer gradually increased. It was revealed by multiple linear regression analysis and Logistic regression analysis that television-watching and computer-using were not only positively correlated with later bedtime, later wake time and shorter sleep duration but also significantly associated with sleep problems such as bedtime resistance, sleep onset delay, sleep duration disorder, sleep anxiety and parasomnia. Conclusion Television-watching and computer-using exert influences on sleep behaviors of sleep/wake patterns, sleep duration and sleep problems. Concerns about the potential negative effects of television-watching and computer-using on sleep behaviors may help to promote healthy sleep patterns and improve sleep quality.