There has been wide ranges of researches on the relationship between melatonin and psychiatric disorders such as affective disorders, sleep disorders, and so on However, the studies concerning the relationship between melatonin and schizophrenia were not common until now. In this article, we reviewed 1) the biochemical aspects of melatonin, 2) the rationale for melatonin deficiency hypothesis in schizophrenia, 3) the relationship between melatonin and structural brain abnormality in schizophrenia, 4) the relationship between melatonin and extrapyramidal symptoms, 5) the relationship between melatonin receptors and serotonin receptors/dopamine, and 6) the relationship between anti psychotics and melatonin. Through these reviews, we attempt to underline the significance of melatonin research in patients with schizophrenia and to suggest the direction of future study.