OBJECTIVES. This study assessed the claim that children's television use interferes with time spent in more developmentally appropriate activities.METHODS. Data came from the first wave of the Child Development Supplement, a nationally representative sample of children aged 0 to 12 in 1997 (N ϭ 1712). Twenty-four-hour time-use diaries from 1 randomly chosen weekday and 1 randomly chosen weekend day were used to assess children's time spent watching television, time spent with parents, time spent with siblings, time spent reading (or being read to), time spent doing homework, time spent in creative play, and time spent in active play. Ordinary least squares multiple regression was used to assess the relationship between children's television use and time spent pursuing other activities.RESULTS. Results indicated that time spent watching television both with and without parents or siblings was negatively related to time spent with parents or siblings, respectively, in other activities. Television viewing also was negatively related to time spent doing homework for 7-to 12-year-olds and negatively related to creative play, especially among very young children (younger than 5 years). There was no relationship between time spent watching television and time spent reading (or being read to) or to time spent in active play.CONCLUSIONS. The results of this study are among the first to provide empirical support for the assumptions made by the American Academy of Pediatrics in their screen time recommendations. Time spent viewing television both with and without parents and siblings present was strongly negatively related to time spent interacting with parents or siblings. Television viewing was associated with decreased homework time and decreased time in creative play. Conversely, there was no support for the widespread belief that television interferes with time spent reading or in active play.www.pediatrics.org/cgi