BACKGROUND: Sleep is essential for children’s growth and development, yet sleep disturbances remain common among preschoolers. Insufficient sleep has been linked to cognitive impairments, behavioral problems, and increased risk of obesity. Nutritional factors, particularly omega-3 fatty acids, may play a role in sleep regulation. Although previous studies have suggested that Eicosapentaenoic Acid (EPA) and Docosahexaenoic acid (DHA) are associated with improved sleep outcomes, yet data on omega-3 status and its relationship with sleep duration among Indonesian preschoolers remain scarce. Therefore, this study was conducted to analyse the association between Omega-3 fatty acids levels and sleep duration among preschool children in Indonesia.METHODS: A cross-sectional survey was conducted among 72 children aged 3–5 years old. Sleep duration and disturbances of subjects were assessed using the Children’s Sleep Habits Questionnaire–Abbreviated (CSHQ-A). Omega-3 fatty acids levels, including α-linolenic acid (ALA), EPA, and DHA, were measures using gas chromatography.RESULTS: The median sleep duration was 11 hours (range 9–13.5 hours). Based on CSHQ-A scores, 93.1% of subjects experienced sleep disturbances. Mean total omega-3 fatty acid concentration was 225.47±80.9 µmol/L. Significant positive corelations were observed between sleep duration and total omega-3 fatty acid (r=0.298; p=0.011), EPA (r=0.233; p=0.049), and DHA (r=0.260; p=0.028).CONCLUSION: Omega-3 fatty acid levels, particularly EPA and DHA, were positively associated with sleep duration in preschool children. These findings provide preliminary evidence of the role of omega-3 in sleep regulation and underscore the importance of considering nutritional factors in efforts to improve sleep quality during early childhood.KEYWORDS: omega-3 fatty acids, DHA, EPA, ALA, sleep duration, preschool children