Depressive symptoms are highly prevalent in the medically ill, and may affect quality of life, social functioning, and compliance and the outcome of treatments for medical illness. There is evidence that depression in medical patients is frequently unrecognised and untreated. Its evaluation requires both the assessment of severity (whether it reaches the clinical threshold of a major depressive disorder) and determination of aetiology (symptomatic or organic mood disorders). Treatment of symptomatic depression follows the treatment, whenever it is feasible, of the underlying medical condition. Antidepressant drugs are the treatment of choice for major depressive disorders in the medically ill, and are well tolerated in patients with a number of medical conditions, provided that specific precautions are heeded. In the medically ill, tricyclic antidepressants appear to still present considerable advantages over second generation antidepressants, such as selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors. Psychotherapeutic interventions have considerable potential, currently largely unexplored in controlled studies, for the treatment of depression in the medically ill. Electroconvulsive therapy (ECT) remains an effective modality for refractory depression and can be used safely in a number of medical conditions.