The objectives of this study were to examine the prevalence of depression in hospitalized, medically ill, older patients with and without congestive heart failure (CHF), and examine correlates, course, predictors of outcome, and treatment of depression in patients with CHF. A consecutive sample of 542 patients age 60 or over admitted to inpatient services of Duke University Medical Center were systematically screened by a psychiatrist for depression using the Diagnostic Interview Schedule; 342 depressed cases and nondepressed controls were identified. Of these, 107 had a primary or secondary diagnosis of CHF. Among patients with CHF, major depression was identified in 36.5%, a rate that was significantly higher than for patients without CHF (25.5%); the difference was largely explained by low rates of major depression in cardiac patients without CHF (17.0%) who had less severe physical illness. Minor depression was also present in 21.5% of CHF patients, but was not more prevalent than in patients without CHF (17.0%). Compared with nondepressed CHF patients, those with depression were more likely to have comorbid psychiatric disorder, severe medical illness, and severe functional impairment. Depressed patients used more outpatient and inpatients medical services, although this was largely due to the severity of their health problems. Patients often remained depressed for a prolonged period, and over 40% failed to remit during the year following discharge. Factors predicting slower remission included nonhealth-related, stressful life events and low social support; physical health factors at baseline had little effect. The majority of depressed CHF patients did not receive treatment for their depression with either antidepressants or psychotherapy, and did not see mental health specialists any more frequently than did the nondepressed. These findings are of concern and have important implications for the diagnosis and treatment of depression in older patients with heart failure.