Sarcoidosis and Wegener's granulomatosis (WG) share membership in the family of granulomatous diseases. Both are systemic processes that have major expressions in common sites, such as the respiratory tract, kidneys, skin, nervous system, eye and orbit, musculoskeletal system, and heart. In spite of these common features, they are sharply divergent in clinical course and pathology, sarcoidosis being a more benign, indolent disease of low mortality, in contrast to the highly lethal more dramatic course of WG. Both entities respond to glucocorticoids, but WG frequently requires cytotoxic agents such as cyclophosphamide. The current concepts of pathogenesis suggest sarcoidosis to involve mainly T-cell mediated mechanisms, whereas in the case of WG the presence of antineutrophil cytoplasmic autoantibodies (ANCA) points toward humeral mechanisms, although T-cells may also be involved.