A 35-year-old woman had a 13-year history of systemic lupus erythematosus (SLE) with recurrent flares since 1972 responding to corticosteroid therapy. In August, 1990 she presented with a 2-month history of dyspnea at rest, 4-pillow orthopnea and paroxysmal nocturnal dyspnea. Respiratory rate was 32-36/min, chest expansion 2 cm and crackles were present at the lung bases. On chest radiograph diaphragms were elevated. Pulmonary function tests (PFT) showed further reduction in lung volumes, maximum inspiratory pressures, maximum expiratory pressures and arterial blood gases. Ventilation/perfusion and gallium lung scans were normal. A diagnosis of "shrinking lungs syndrome" was made. Treatment with 40 mg of prednisone resulted in resolution of the patient's shortness of breath. PFT showed improvement in all variables. Corticosteroid therapy for acute "shrinking lungs syndrome" in active SLE can improve symptoms and pulmonary function.