Several studies have shown that depression is an important predictor of morbidity and mortality in patients with ischaemic heart failure. We have investigated whether clinically recognised depression is linked to mortality in patients with non-ischaemic heart failure due to dilated cardiomyopathy (DCM) in the Royal Brompton Hospital (RBH), a tertiary cardiac centre located in London, UK. We retrospectively examined a cohort of 396 consecutive adult patients with DCM who satisfied our inclusion and exclusion criteria identified from an echocardiographic database and the hospital medical records. Mean age was 53+/-15 years. In all, 83 patients (21%) were clinically depressed, the majority of which (60%) were taking antidepressant therapy. After a follow-up period of 48 months, 83 (21%) patients died, 15 (4%) underwent cardiac transplantation and 130 (33%) were readmitted; 29 (35%) of the deaths and 40 (31%) of the readmissions were among clinically depressed patients. After 5 years, clinically depressed patients had significantly higher mortality and readmission rates than non-depressed; 36 vs. 16% (hazards ratio for death, 3.0; 95% CI, 1.4-6.4; P=0.004), and 87 vs. 74% (hazards ratio for readmission, 0.25; 95% CI, 0.07-0.90; P=0.03), respectively. The risk of depression was greatly increased in the presence of other recognised adverse clinical variables at baseline. Depression increases the risk of death and readmission in patients with heart failure secondary to non-ischaemic DCM. The risk associated with depression appears to be greatest among patients with milder disease, those with a shorter duration of symptoms and those demonstrating a lower systolic or diastolic blood pressure, renal impairment, or a restrictive left ventricular physiology on echocardiography. Interventions targeted at reducing depression warrant further study as a possible way to improve quality of life and/or outcome in patients with heart failure.