Our study revealed that mucosal thickening, bone thickening, bone destruction, and orbital invasion mass were major CT findings in patients with GPA. Intranasal findings such as granulations, crusting, and necrosis were seen in the active phase; moreover, saddle nose, loss of turbinate, and nasal septal perforation were subsequently seen in the course of the disease. Sinonasal findings of GPA vary depending on the disease stage and period.