Massive pulmonary hemorrhage confirmed by pathologic examination occurred in three of 12 patients with systemic lupus erythematosus (SLE) complicated by lung disease. Two patients died. Hemorrhage was clinically unrecognized in two cases. The third patient survived after an open lung biopsy and an increase in prednisone therapy. In the absence of hemoptysis, awareness of the possibility of pulmonary hemorrhage in patients with SLE and a high index of suspicion are necessary for early recognition of this uncommon but potentially fatal complication.