Sleep is important for health and quality of life at all ages, and poor sleep interacts with many medical conditions. Somatic and psychiatric diseases, and unfavourable habits and life-style factors, increase the propensity to insomnia in older persons. As health deteriorates with age, sleep becomes poorer. Heart disease and stroke, cancer, painful conditions, breathing disorders and nocturnal polyuria syndrome often disturb sleep. Dementia and depression, which are often associated with sleep disturbances, are also more prevalent in the elderly. Moreover, true age-related sleep deterioration occurs after the age of 75 years. Attempts to improve sleep should first and foremost be focused on elimination of somatic and psychiatric symptoms as far as possible, and on modification of lifestyle factors that may affect sleep quality. For short term treatment, hypnotics are appropriate; for longer periods, nonpharmacological methods, for example light therapy or behavioural modification techniques, should be considered, as many hypnotic drugs are less suitable for long term use. However, there are situations when sleep medication must continue for long periods, especially in elderly patients with severe diseases and poor quality of life. In these patients, careful individualisation of therapy is appropriate.