Depression is a common psychiatric problem in old age. The magnitude of the problem will become greater as this segment of the population grows. Depression is often overlooked in the elderly, contributing to a greater risk of suicide in this group than in younger patients. Depression may be masked by hypochondriasis or somatization. Special problems in diagnosis include bipolar disorder, pseudodementia, pathological grief, and organic mood disorder as related to medications or physical illness. Pharmacokinetic changes with aging need to be kept in mind by physicians treating the elderly with antidepressant medications. Tricyclic antidepressants are the traditional first line pharmacologic agents. Tricyclics with a low side effect profile, such as desipramine or nortriptyline, are generally preferred. However, newer medications including serotonin reuptake inhibitors and bupropion are becoming more widely used. Other medications, including monoamine oxidase inhibitors, lithium, and stimulants, also have a place in the treatment of depression in old age. Electroconvulsive therapy is a useful treatment for patients with treatment-resistant or psychotic depression. Psychotherapy in the elderly has not been well studied, but is believed to be effective if patients are properly selected for therapy and appropriate modifications are made.