Idiopathic pulmonary arterial hypertension is a disease involving small muscular pulmonary arteries and arterioles. Treatment with prostacyclin analogs and endothelin receptor antagonists is the cornerstone of therapy in these patients. Recent evidence suggests that phosphodiesterase-5 inhibitors such as sildenafil may improve functional capacity and hemodynamics in patients with pulmonary arterial hypertension. Despite these advances, pulmonary arterial hypertension remains a deadly and progressive disease and it has been suggested that combination therapy aimed at multiple targets may produce a greater improvement while minimizing adverse effects. We report three patients who declined after initial improvement on bosentan and subsequently showed an improvement in their functional capacity and brain natriuretic peptide (BNP) with the addition of sildenafil. This benefit has been sustained over a mean follow-up period of 19 (range 12-24) months.