Pulmonary arterial hypertension complicated by decompensated cor pulmonale is a challenging clinical problem with few effective therapeutic options. B-type natriuretic peptide is a pluripotent hormone that promotes diuresis and natriuresis, vasodilates systemic and pulmonary vessels, and reduces circulating levels of endothelin and aldosterone. It may represent a possible therapeutic strategy for decompensated cor pulmonale in the same manner that it is used to treat decompensated left heart failure. The authors report their experience with B-type natriuretic peptide as adjunctive therapy for pulmonary arterial hypertension complicated by decompensated cor pulmonale. A detailed case report is presented followed by the evaluation of a series of 11 cases occurring in eight patients from December 2002 through April 2004.