Introduction: Melatonin, an endogenous chronobiotic substance, is increasingly used for the management of sleep problems in older adults because of their apparent efficacy and safety. Here, we aimed to assess the effectiveness of melatonin in the treatment of primary insomnia in the elderly (≥55 years) compared with benzodiazepines, zopiclone and placebo accordingto available evidence in past five years. Methods: Systematic review of the literature. Results: Compared with placebo, apparently melatonin improves the quality and sleeping habits, not the sleep onset latency on subjective or objective measures (polysomnography); unlike other hypnotic drugs, Melatonin does not alter sleep architecture or generate daytime symptoms. Conclusions: No evidence was found to support the use of melatonin in adults over 55 years to reduce sleep latency, increased total sleep time, improved sleep efficiency, decreased nocturnal awakenings or improving quality sleep. Further study is necessary to advance comparing melatonin treatment to placebo and other medications.