Sleep evaluation can be essential in the treatment of dementia because sleep-related issues are common in dementia, often treatable, affect patient function, and are a major cause of caregiver distress. This article provides a practical approach to treatment of sleep in patients with dementia. Certain specific sleep disorders can be associated with certain underlying disorders and greater knowledge of these relationships is leading to more refined treatment approaches. Whether a sleep-related disorder such as obstructive sleep apnea, or limited sleep time, predisposes to the development of dementia is an active area of research.