Successful vasodilator therapy of a 19 year old woman with primary pulmonary hypertension is described. Long-term home oxygen therapy during sleep (2 1/min, 8 hours) in combination with vasodilator drugs (prazosin 2 mg and long-acting ISDN 20 mg bid) and an anticoagulant (ticlopidine 100 mg bid) brought significant reduction of pulmonary artery pressure and a rise of cardiac output 3 years later. This combination therapy may be effective in selected patients with primary pulmonary hypertension.