Coronary artery disease, heart failure and depression are all highly prevalent after 60 years of age. They significantly affect quality of life and represent a major economic burden for society. Some epidemiological and observational studies suggest that depression is an independent risk factor for the onset and progression of ischemic heart disease and heart failure. Patients with depression are more likely to develop ischemic heart disease, and they are more likely to die or to have a recurrence after myocardial infarction. Heart failure is frequently associated with depression, and this combination carries an increased risk of complications and mortality. Several factors seem to link depression with cardiovascular events and poor outcome, including poor adherence to treatment, sympathetic stimulation, endothelial dysfunction, low heart rate variability, and abnormal platelet function. There is strong evidence that depressive symptoms are a negative prognostic factor in patients with heart failure and coronary heart disease. Treatment of depression improves quality of life, but its impact on the outcome of heart diseases is controversial. Selective serotonin reuptake inhibitors seem preferable to tricyclic antidepressant for depressive patients with cardiac diseases, because of their good tolerability and lack of cardiovascular effects.