Sleep disorders, including insomnia are common in older people. Since the sleep problems are generally subjective, intensive medical interviews using various sleep questionnaires are critical in the diagnosis and assessment. As an objective examination of sleep quality, an overnight polysomnography at a hospital is the gold standard, but sleep diary and actigraphy, which record sleep for a prolonged period at home, are useful to examine the sleep habit and sleep phase. In older people, the discrepancy between sleep diary and actigraphy sometimes become broader, and the prevalence of comorbidity increase. Thus, the systematic assessment using both subjective and objective measurements becomes more important.