Wegener's granulomatosis (WG) is a potentially fatal disease in which early diagnosis and administration of immunosuppressive agents is essential to successful treatment. The disease is characterized by necrotizing and granulomatous inflammation and vasculitis of the respiratory tract and kidney. The variety of clinical presentations often makes the diagnosis difficult. We present a case of WG in a 24-year-old male in whom the diagnosis was first suggested after cytologic examination of a nasal scrape for sinusitis. The smears showed numerous neutrophils and occasional multinucleate histiocytic giant cells. Reactive epithelial cells from the respiratory mucosa were also present. No organisms were identified on Gram or acid-fast stain. Considering the clinical setting, the diagnosis of WG was suggested. Subsequent renal biopsy revealed necrotizing and crescentic glomerulonephritis, and the patient was successfully treated with cyclophosphamide. This case illustrates a rapid and noninvasive method by which the diagnosis of WG may be suspected early in the course of the disease.