Introduction: Electroencephalography (EEG) is useful in seizure diagnosis. It needs cooperation and immobility of the person and if a child does not naturally sleep, pharmacological agents will be used to induce sleeping. The purpose of this study was to investigate efficacy and side effects of oral melatonin in sedation induction for EEG of children. Methods: In a quasi- experimental study, efficacy of single dose of 0.3mg/kg melatonin in achieving adequate sedation (Ramsay sedation score of four) as well as its success in recording of EEG and its side effects in 40 children were investigated from September 2011 to March 2012. The participants aged 1-8 years who referred to EEG Unit of Shahid Sadoughi Hospital, Yazd, Iran and did not naturally sleep and immobilize. Results: Sixteen girls (40%) and 24 boys(60%) with mean age of 2.82 ±1.91 years were investigated. Adequate sedation and recording of EEG was achieved in 29 (72.5 %) children. The drug was more effective in success of recording of EEG in less than two year old children (70.6% vs. 30.4% in two years old and more and pvalue= 0.04) as well as in those with developmental delay (93.3% vs. 60% in normal developmental status and pvalue =0.02). No serious side effects were seen in the patients. Conclusion: Melatonin is a safe and effective drug in sedation induction for EEG in children especially in those less than two years old and in children with developmental delay