Heart failure (HF) and depression are debilitating diseases with significant effects on functional status and real and perceived quality of life. Despite many advances in therapy for HF mortality remains high. Depression and HF have been recognized to coexist but this does not imply a causative relation. Depressed patients develop more symptoms, have worse compliance with medication regimens, are slower to return to work and social activities, and seem to have a poorer quality of life. In patients with known cardiac disease depression also predicts future events independent of disease severity and other risk factors such as smoking or diabetes mellitus. In conclusion, this review attempts to address the cause/effect relation, if any, between HF and depression and the role of treatment of depression in the setting of HF.