Background: The continuous revolution of electronic media has many negative effects on preschool children as sleep disturbance, behavioral problems, obesity, cognitive and language problems, and social-emotional delay. Aim of the study: The aim of the present study was to assess the effect of excessive electronic media exposure in developing sleep disorders among preschool children. Subjects and method: Research design: A prospective descriptive research design was used to accomplish the aim of the present study. Setting: The present study was conducted at four governmental nursery schools in Zagazig city. Subjects: 160 mothers of preschool children were selected by using a multistage cluster sampling technique. Tools of data collections: Data were collected by using an interview questionnaire sheet composed of three parts: Sociodemographic data, Excessive electronic media exposure questionnaire, and Sleep disturbance scale for children (SDSC) in preschool age. Results: The study results revealed that 96.7% of children who exposed to media more than 4 hours daily have high sleep disorders at second measurement. Additionally, there were a statistically significant differences regarding sleep disorders domains (initiation/maintenance, excessive somnolence and sleep-wake transition disorders) at second measurement compared to first one. Conclusion: The study concluded that increasing hours of daily exposure to media accompanied with high level of sleep disorders. Recommendations: it is recommended that Health education programs for parents about the negative effects of excessive exposure to electronic media on quality and quantity of sleep among preschool children.