Pulmonary arterial hypertension (PAH) is defined as a group of diseases characterized by identical pathological changes of the pulmonary microcirculation. The disease is associated with poor progno¬sis and before the introduction of intravenous prostacyclin, median life expectancy from the time of diagnosis was 2.8years. Continuous intravenous administration of epoprostenol improved survival of patients with PAH and currently is considered as the most effective therapy. Nevertheless, this therapy presents significant difficulties in the modality of administration and also systemic side-effects. Owing to the problems with epoprostenol, new prostacyclin analogues administered subcutaneously (trepros-tinil), orally (beraprost) and by inhalation (iloprost), have been sought for the treatment of PAH. Other emerging therapies for treatment of PAH include endothelin-1 receptor antagonists, phosphod¬iesterase inhibitors and L-arginine. The impact of new therapies on survival of patients with PAH and also the combination of diverse drugs need further investigation. Pneumon 2005,18(2):144-155.