Increased pulmonary precapillary vascular resistance due to vasoconstriction and vasoproliferative processes is the basic pathophysiological mechanism in the development of pulmonary hypertension (PH). With the exception of pulmonary venous hypertension, where the primary cause of PH is left ventricular failure or mitral valvular disease, all the other PH categories will benefit to a greater or lesser extent from pulmonary vasodilator and antivasoproliferative therapy. Today, for this purpose, in addition to intravenous prostacyclin (epoprostenol), which is restricted to severe pulmonary arterial hypertension (NYHA class IV and late class III), other therapeutic options such as treatment with more stable prostacyclin analogs (oral beraprost, aerosolized iloprost), endothelin-receptor antagonists (bosentan) or phosphodiesterase inhibitors (sildenafil) are also available and these are especially useful for the treatment of the early stages of the disease. The recent progress in medical therapy has markedly increased the life expectancy in patients with pulmonary arterial hypertension and substantially improved their quality of life. Chronic hemodialysis (HD) patients show higher endothelin-1 (ET-1) activity in comparison to healthy individuals and there is evidence that the increase of pulmonary vascular resistance in these patients is at least in part mediated by ET-1. Recent data show good results after PH therapy with the endothelin-receptor antagonist bosentan in HD patients. Also prostacyclin and its analogs, as well as phosphodiesterase inhibitors, can be useful for the treatment of pulmonary hypertension in patients with chronic renal failure.