The diagnosis of pulmonary hemorrhage syndromes (PHS) rests on a body of clinical and paraclinical evidence found in all etiologic forms. Usually, the combination of hemoptysis, iron deficiency anemia, and roentgenologic infiltrates is easy to recognize; in more atypical cases, alveolar bleeding can be demonstrated by determination of the Golde score on bronchoalveolar lavage specimens. Whereas clinical features are nearly invariable, etiologies cover a broad spectrum including some glomerular diseases, idiopathic pulmonary hemosiderosis, connective tissue disorders, pulmonary conditions related to compromised immunity, airborne pulmonary aggressions, and some apparently primary vascular disorders. Regardless of the severity of clinical features at presentation, pulmonary hemorrhage syndromes are always a diagnostic and therapeutic emergency.