At present there is no approved therapy for inoperable chronic thromboembolic pulmonary hypertension. Bosentan is a drug which is effective for primary pulmonary hypertension. Xavier Jaïs et al published the results of BENEFiT (Bosentan Effects in iNopErable Forms of chronIc Thromboembolic pulmonary hypertension), a Randomized, Placebo-Controlled Trial in a recent issue of Journal of American College of Cardiology (J Am Coll Cardiol, 2008; 52:2127-2134). 157 patients participated in the trial and they were randomized to bosentan or placebo for 16 weeks. Pulmonary vascular resistance (PVR) was reduced and the cardiac index improved in the bosentan treated group, but the 6-minute walk distance did not imporve. Further trials are needed to asssess whether the improved pulmonary vascular resistance will translate into long term clinical benefits. Bosentan treatment was well-tolerated and appears promising for patients with chronic thromboembolic pulmonary hypertension.