The World Health Organization symposium offers a new treatment-oriented classification of pulmonary hypertension based on an improved understanding of its pathophysiology. Regardless of the etiology, severe or unrelieved pulmonary hypertension leads to right heart failure. Symptoms and signs of pulmonary hypertension are often subtle and nonspecific. As a result, a significant delay between the onset of symptoms and the diagnosis of pulmonary hypertension is common. Echocardiography with Doppler flow is the most useful study to evaluate patients suspected of having pulmonary hypertension. The suspected diagnosis of pulmonary hypertension should then be confirmed by right heart catheterization. If present, further evaluation may include oxygen assessment, pulmonary function testing, high resolution computed tomography of the chest, and ventilation-perfusion lung scanning. Treatment of pulmonary hypertension requires uncommon expertise. General measures include correction of the underlying cause, reversal of hypoxemia and judicious use of diuretics. Advances in vasodilator therapy have increased treatment options beyond calcium channel blockers and intravenous epoprostenol. Lung transplantation remains an option for select patients with pulmonary hypertension not responding to medical management.