Introduction. Circadian rhythms are variations in physiology and behaviour that persist with a cycle length close to 24 hours. Such biological rhythms include the sleep and wake cycle, alertness, daily cycles of hormonal secretion (e.g., melatonin and cortisol, ghrelin and leptin), body temperature cycle and blood pressure regulation. Circadian rhythms must be synchronized or entrained to the 24-hour day regularly. This process of entrainment occurs through regular exposure to daily exogenous environmental cues known as zeitgebers. The most potent zeitgeber is light that activates photoreceptors in the retina inhibiting pineal gland secretion of the sleep-promoting hormone, melatonin. Polychromatic white light (white light enriched in blue) having a significant impact on this training. Aim of the study. To explore the influence of screens light exposure on the circadian rhythm in schoolchildren, in particular on the quality and quantity of sleep. Materials and methods. There were used “PubMed MEDLINE” database to select relevant articles published from 2010 to 2019, using the keywords: “technology use and biological rhythm (sleep)”, light exposure, electronic media and sleep/circadian rhythm. Results. We identified 24 papers that have investigated the relationship between circadian rhythm/sleep and electronic media in school-aged children, including television viewing, use of computers, electronic gaming, and the internet, mobile telephones, and musicThere have been identified behaviour and sleep-related problems because of internet and telephone overuse, as well as social network activities, game consoles and television viewing, the number of devices in the bedroom and turning-off time. The spectral profile of light emitted by screens impacts on circadian physiology, alertness, cognitive performance levels but also for weight gain, metabolic disorder, depression, mood disorders, cancer and heart disease. Conclusions. Many schoolchildren used multiple forms of technology late into the night without prudence or restrictions. Subsequently, their ability to stay alert and fully functional throughout the day was impaired. Both parents and schoolchildren should be informed about the influence of technologies on sleep, effects of blue light exposure, sleep hygiene and early adoption of healthy sleep habits and prevent sleep problems.