Screen-time activities are often used as proxies for sedentary time. We studied associations of self-reported television (TV), computer and total screen-time with accelerometer-derived total sedentary time in European children (10-12 years). Analyses showed significant positive associations between TV, computer and total screen-time with total sedentary time for the total sample, however, the explained variance was low and stratified analyses only revealed a significant positive association between total screen-time and total sedentary time in boys and between computer time and total sedentary time in Dutch children. This suggests that self-reported TV and computer time do not adequately reflect total sedentary time in schoolchildren.