We describe 12 patients with systemic lupus erythematosus (SLE) who developed massive pulmonary hemorrhage with very active disease. Other causes of pulmonary bleeding were excluded. Eleven of the 12 patients died, but only 4 had hemoptysis. Massive pulmonary hemorrhage should be suspected, even in the absence of hemoptysis, in severely ill patients with lupus who develop acute respiratory distress with bilateral pulmonary infiltrates and a drop in hemoglobin of 3 or more g/dl. Because of the deadly nature of this complication of SLE, when it is suspected, intensive corticosteroid and immunosuppressive treatment should be instituted.