Wegener's Granulomatosis is a rare multisystem autoimmune disease characterized by necrotizing granulomatous inflammation of the upper and lower respiratory tract, glomerulonephritis, and vasculitis. The etiology of WG remains unknown, although several exogenous factors have been suggested to be relevant. Most clinical characteristics of this disease are nonspecific, making clinical diagnosis challenging. Histopathological examination of lesional tissue is not pathognomonic, but it is an essential investigation to confirm the presence of the disease and exclude other disorders. This paper reviews the peculiar aspects of this rare granulomatous disease with respect to diagnosis, laboratory features, and treatment.