About one in ten older people are affected by major depression, especially those with chronic medical illnesses and/or cognitive impairment. Late-life depression has a major impact on the affected person, his or her caregiver, the health system and the wider society. The elderly population is particularly at risk of being underdiagnosed and inadequately treated. Assessment should seek to diagnose late-life depression, to identify factors interacting with the mood disorder, self-harm or suicide risk and any features of cognitive or functional impairment. Treatment is usually multimodality involving lifestyle modification, psychotherapy and pharmacotherapy. Electroconvulsive therapy may be indicated in older people with severe or treatment-resistant depression. Management of late-life depression must always take into account coexisting medical illnesses together with their bidirectional effects on depression and cognitive impairment.