The majority of patients with classic Wegener's granulomatosis present with symptoms of head and neck disease; accordingly, accurate interpretation of biopsy specimens from these sites is essential. This report details the histologic findings in 126 head and neck biopsy specimens from 70 patients (36 male and 34 female). Tissues were obtained from the following sites: 60 nasal, 27 paranasal sinuses, 17 laryngeal, five periorbital, five oral, four middle ear, three mastoid, two external ear, and three salivary gland. Vasculitis, necrosis, and granulomatous inflammation together were seen in only 16% of all head and neck biopsy specimens. Both vasculitis and granulomatous inflammation were seen in 21% and vasculitis and necrosis in 23% of the biopsy specimens reviewed. We discuss the problems in differential diagnosis, particularly the importance of excluding granulomatous infectious processes, which can imitate the histopathologic features of Wegener's granulomatosis. Based on this study, we propose criteria for the diagnosis of Wegener's granulomatosis based on biopsy specimens from the head and neck region.