We report a case of sarcoidosis presenting with cor pulmonale of a greater severity than would be expected from the degree of hypoxia and pulmonary fibrosis. Right heart catheterization revealed that mean pulmonary artery pressure was markedly increased (42 mm Hg), was not reduced by supplemental oxygen, but was reduced significantly (25 mm Hg) after 16 weeks of therapy with corticosteroids. Improvement in symptoms and pulmonary function was maintained for an 18-month period of observation after cessation of corticosteroid therapy.