The systemic vasoconstriction that is characteristic of patients with congestive heart failure involves arteriolar constriction, reduction in arterial compliance and reduction in venous capacitance, all of which contribute to the increased impedance and increased preload that aggravate the hemodynamic abnormality. Mitrates are effective in increasing arterial compliance and venous capacitance and thus have a favorable acute hemodynamic effect in heart failure. Long-term studies suggest that this favorable effect is maintained in response to high dose oral isosorbide dinitrate therapy and that it is associated with relief of symptoms and improved exercise tolerance. When combined with hydralazine, isosorbide dinitrate therapy has been shown in the Veterans Administration study to prolong survival in patients with class II and III congestive heart failure. Therefore, long-term nitrate therapy appears to have an important potential in patients with heart failure. It may now be appropriate to use nitrates not only to relieve symptoms, but also to improve long-term outlook in this syndrome.