Heart failure affects 4.8 million people in the United States. Patients depressed after myocardial infarction have increased morbidity and mortality. Only a few studies have investigated the effects of depression in patients with heart failure. The incidence of depression in heart failure ranges from 13% to 77.5%. Men with heart failure are more likely to become depressed than the general population. Depression incidence is higher in hospitalized patients with heart failure than in stabilized outpatients. In patients with heart failure, depression is associated with mortality. Physiologic changes, which occur in depressed patients, have been implicated as possibly contributing to the increased mortality. Nurses have a major role in the management of patients with heart failure and can be pivotal in the detection and treatment of depression in these patients. Reduction in depression is likely to decrease morality in patients with heart failure.