A case is reported of a 6-year-old boy who had developed pulmonary hypertension because of obstruction to the pulmonary venous flow by severe stenosis of the pulmonary veins at their junction with the left atrium. The development of collateral circulation through the bronchial vessels led to early, severe hemoptysis. The course was complicated by the development of pulmonary arterial and venous thrombi and hypertensive arteritis.