Five distinct clinical syndromes of pulmonary angiitis and granulomatosis are currently recognized: Wegener granulomatosis, lymphomatoid granulomatosis, necrotizing sarcoid granulomatosis, bronchocentric granulomatosis, and allergic angiitis and granulomatosis (Churg-Strauss syndrome). Patients typically present in middle age with fever, cough, hemoptysis, dyspnea, or chest discomfort. Upper airway involvement such as sinusitis suggests Wegener granulomatosis. Medical renal disease is associated with Wegener granulomatosis and Churg-Strauss syndrome. Asthma may be present in bronchocentric granulomatosis and Churg-Strauss syndrome. Pathologic examination of these entities demonstrates vasculitis, granulomatous inflammation, and parenchymal necrosis. The radiologic manifestations of pulmonary disease are varied, but the most typical appearance is that of multiple nodules or masses that may demonstrate cavitation. Diffuse multifocal air-space opacities with or without cavitation may also be seen. Pulmonary hemorrhage is a well-known presenting manifestation of Wegener granulomatosis and, less commonly, of Churg-Strauss syndrome. Because of the multifocal lung involvement in these diseases, pulmonary metastases and infectious causes are often considered in the differential diagnosis. Affected patients are treated with cytotoxic agents and corticosteroids. The prognosis is variable, depending on the specific syndrome, but may be favorable in the absence of significant complications.