Recombinant human B-type natriuretic peptide (BNP) is a promising new agent in the management of heart failure. The pharmacologic properties of BNP make it desirable to use in a subset of patients after cardiac surgical operations. Among these therapeutic potentials is the effect on markedly reducing pulmonary vascular resistance and central venous pressure with mild systemic vasodilatation. In addition, BNP directly effects the kidneys to promote natriuresis. We believe this agent to be useful in the treatment of the postcardiac surgery patients with left ventricular dysfunction and mild to moderate renal insufficiency. This report summarizes our experience in 2 patients.