Depression is associated with elevated rates of cardiovascular morbidity and mortality. This elevation seems to be due to a significantly increased risk of coronary artery disease and myocardial infarction and, once the ischemic heart disease is established, sudden cardiac death. Recent data suggest that the increased rates of cardiovascular disease in patients with depression may be the result of one or more still-unrecognized underlying physiological factors that predispose a patient to both depression and cardiovascular disease. Two possibly related factors that may have a causal relation with both depressive disorders and cardiovascular disease are an omega-3 fatty acid deficiency and elevated homocysteine levels. We present the available data connecting cardiovascular disease, depression, omega-3 fatty acids, and homocysteine. In addition, we suggest research strategies and some preliminary treatment recommendations that may reduce the increased risk of cardiovascular mortality in patients with major depressive disorder.