Depressive disorder is the most common mental health problem in older people. Health professionals mainly come into contact with those who are most susceptible to depression, including older people who live in residential facilities and the frail with acute or chronic physical illness. Quite often, such individuals also exhibit multiple pathology. Under these circumstances, health professionals may have an exaggerated view of the extent of depression among the elderly, causing them to overlook depressive disorders that they may have developed. Organic factors, including alcohol and iatrogenic drugs, must be ruled out in the aetiology. Physical ill health must receive optimum treatment. The choice of antidepressant drug is based on the side-effect profiles and potential drug-drug interactions, rather than on the degree of therapeutic efficacy. Treatment should be multimodal and multidisciplinary, with the aim of complete recovery and not simple improvement. By using a range of treatments, most patients will recover, though keeping patients well is more difficult. Treatment should be continued for at least 12 months. Many patients who could benefit from long-term maintenance therapy do not receive it. With optimum management the prognosis is at least as good as that for any other stage of adult life.