We report two cases of Wegener's granulomatosis with the unusual manifestation of diffuse alveolar hemorrahge. One patient with well-documented Wegener's granulomatosis developed alveolar hemorrhage 4 weeks after leukopenia necessitated the discontinuation of cyclophosphamide. The second patient presented with pulmonary hemorrhage and died 10 days after an open-lung biopsy in which histologic features of Wegener's granulomatosis were overshadowed by alveolar hemorrhage. Lung biopsies in both cases showed marked alveolar hemorrhage and pulmonary capillaritis. The importance of recognizing capillaritis and other subtle histologic features of Wegener's granulomatosis are emphasized.