Wegener's granulomatosis is a distinct clinicopathologic entity characterized by granulomatous vasculitis of the upper and lower respiratory tract and kidneys. A 56-year-old Japanese man with Wegener's granulomatosis died of intraperitoneal hemorrhage from a ruptured aneurysm of his left gastric artery. Histological findings revealed necrotizing granulomatous vasculitis involving this artery. No previously published reports have described Wegener's granulomatosis patients with aneurysms in such a large artery. We conclude that this case represents either an atypical form of Wegener's granulomatosis or a polyangiitis overlap syndrome of Wegener's granulomatosis and classic polyarteritis nodosa.