OBJECTIVE: This open-label study examined the effects of ramelteon on cognitive functions in 10 outpatients with schizophrenia. METHODS: Ramelteon (8 mg/day) was administered to 10 patients with schizophrenia for six months. The verbal fluency test, Trail-Making Test, the Wisconsin Card Sorting Test, the Stroop Test, the Digit Span Distraction Test, Iowa Gambling Task, the Rey Auditory Verbal Learning Test were evaluated at baseline and 6 months after treatment with ramelteon. RESULTS: Ramelteon improved significantly the scores of Rey Auditory Verbal Learning Test. Additionally, ramelteon exerted improvements in the verbal fluency and Iowa Gambling Task in 4 patients. CONCLUSION: Ramelteon could be a potential therapeutic drug, in adjunctive treatment of learning and memory deficits seen in patients with schizophrenia.