Background: School age children are growing up in an era saturated with screen-based media devices, which affected children's overall health. Sleep is crucial for school age children's healthy development. Excessive screen-based media devices use can disrupt children's sleep habits and pattern. Aim: The study aimed to assess the relationship between excessive screen-based media use and sleep pattern of school age children. Design: A correlational descriptive research design was used in the study. Setting: The present study was carried out in six elementary schools in Ismailia City. Sample: A cluster sample (341) of school age children at the previously mentioned settings Tools of data collection: The data were collected using two tools namely Children's Sleep Habits Questionnaire (CSHQ) and Screens questionnaire. Results: The most frequently screen-based media device used by school age children was TV. Two thirds of the studied children used screen-based media devices excessively and most of them had sleep disorders. There was a statistically significant relationship between excessive screen-based media devices use and children's sleep pattern (P< .001). Almost 7 % of the variation of sleep pattern explained by screen media devices use. Conclusion: Excessive screen-based media devices use negatively affect children's sleep pattern. Recommendations: An urgent intervention to increase awareness of parents is needed to limit their children's screen-based media use and so mitigate its negative effect on their sleep pattern.