A growing body of evidence suggests that late-onset depression (depression occurring for the first time in later life) differs from early-onset (recurrent) depression in terms of clinical features, aetiology, neuroanatomical substrates and prognosis. Some evidence suggests that late-onset depression is more associated with somatic symptoms, cognitive deficits, cerebral structural abnormalities, vascular disease ('vascular depression') and poorer treatment outcomes than is early-onset depression. Both general adult and old age psychiatrists face the challenges of managing late-onset depression. In this article we attempt to clarify specific issues relating to late-onset depression in terms of clinical features, aetiology, treatment response and prognosis.Hannele Variend is an academic specialist registrar in general adult psychiatry working in the Yorkshire Deanery. Y. Vishnu Gopal is a consultant psychiatrist at the Hartington Unit (Royal Hospital, Chesterfield S44 5BL, UK. Email: vgopal@doctors.org.uk). His interests include assessment and management of cognitive dysfunctions.