This chapter discusses granulomatous diseases of the nose and paranasal sinuses, where wide spectrum of infectious, inflammatory and neoplastic diseases can produce granulomatous inflammation in the nose and paranasal sinuses. Granulomas are characterized by lesions consisting of a focus of chronic inflammation that includes macrophages transformed into epithelium, such as cells, with a collar of mononuclear leukocytes. The three major categories of granulomatous disease include the inflammatory, infectious, and neoplastic varieties. The inflammatory group includes diseases like Wegener’s granulomatosis (WG), Churg–Strauss syndrome (CSS), sarcoidosis, and cholesterol granuloma (CG). The neoplastic group includes various T-cell lymphomas and was previously termed midline lethal granuloma. The acute vasculitic symptoms of WG can be attributed to the result of granulomatous inflammation and vasculitis in the upper airway. Sarcoidosis is a systemic granulomatous disease afflicting primarily young to middle-aged adults.