Functional neuroimaging methods provide a means to understand brain function in patients with sleep disorders. This paper summarizes functional neuroimaging findings in sleep disorders patients, and studies addressing the pharmacology of sleep and sleep disorders. Areas in which functional neuroimaging methods may be helpful in sleep medicine, and in which future development is advised, include: 1) clarification of pathophysiology; 2) aid in differential diagnosis; 3) assessment of treatment response; 4) guiding new drug development; and 5) monitoring treatment response.