Approximately 74-94% patients with Parkinson's disease have sleep disorders: such as frequent awakening, excessive daytime sleepiness, nightmares, nocturnal cramps, REM sleep behavior disorders and so on. In contrast, the relationship between physiological mechanism of sleep and the dopamine systems are still obscure, because the dopamine systems are not directly related neither initiating or maintaining sleep system nor awaking system. However, most of all the dopaminergic drugs were reported to induce sleepiness or sleep attacks in the patients with Parkinson's disease. So, physicians must inform patients with Parkinson's disease warning the excessive daytime sleepiness and sleep attack. In this article, I suggest the mechanisms of sleep disorders on Parkinson's disease from the physiological points of view, and how to manage these problems.