Granulomatous diseases of the lung may have clinical, roentgenographic, and pathological features that closely mimic respiratory tract infections. The protean manifestations of sarcoidosis allow confusion with a wide variety of infectious diseases. Acute hypersensitivity pneumonitis closely mimics an infectious illness; even subacute or chronic presentations may be mistaken for infections. Less commonly, the manifestations of intravenous talc granulomatous disease may also mimic infection.