Background: obesity is a major global health problem with more than 200 million obese men and almost 300 million obese women. Melatonin is a well-known molecule for its involvement in circadian rhythm regulation and has multiple pathological actions including control of appetite, sleep wake cycle and metabolic syndrome.

Aim: to estimate the effect of melatonin supplements on obese patients on a calorie restricted diet in comparison to patients on lifestyle measures only in the form of weight loss, waist circumference and sleep quality.

Subjects and Method: one hundred patients with body mass index > 24 were collected, fifty patients were started on melatonin 5 mg with calorie restricted diet and they were compared to fifty patients who were kept on lifestyle measures. After twelve weeks, patients were re-assessed for weight, waist circumference and sleep duration and quality and the development of any side effects. Data analyzed using paired t test.

Results: patients’ group who were treated with melatonin has shown significant reduction in body weight (91.58. Vs 92.88, p value <0.0004) and waist circumference (99.36 +- 10.73 vs 101 +-10.51, p value< 0.0064). Patients treated with melatonin show improved insomnia severity index (5.47+-0.8 vs 9.08 +-3.58, p value <0.0001). 60% of patients noticed decreased appetite,35% reported daytime sleepiness and fatigue, 25% had dizziness and 20% had mild nausea.

Conclusion: Melatonin significantly reduces the body weight, waist circumference and appetite more than placebo, it has been shown to be safe supplement and helpful in patients with sleep disturbance and obesity.