Patients with psychiatric disorders, including schizophrenia, are reported to suffer from sleep disorders. In this study, we investigated the effects of lurasidone, an atypical antipsychotic, on sleep architecture in rats using sleep electroencephalography. The course of sleep in rats was classified into 3 stages: WAKE, non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep. Lurasidone shortened REM duration and prolonged the mean duration of one bout in WAKE and NREM. Quantitative frequency band analysis during NREM sleep revealed that lurasidone increases slow waves and decreases fast waves. These results suggest that lurasidone ameliorates sleep disorders associated with psychosis.