Wegener's granulomatosis (WG) is a multisystemic disease of unknown etiology characterized by necrotizing vasculitis and granulomatous inflammation (1-3). The disease typically involves the upper airways, lungs and kidneys, and gastrointestinal involvement is uncommon. Described here is a 33-year-old man who presented at the hospital with abdominal pain. Colonoscopy revealed multiple ulcers, including round ulcers, throughout the large intestine. Small bowel ulcers were detected by double balloon enteroscopy (DBE). Further study confirmed that these ulcers were caused by gastrointestinal complications of WG. The patient was administered prednisolone and cyclophosphamide and remains in remission. This case indicates the importance of considering a gastrointestinal complication of WG as the potential cause of abdominal symptoms among WG patients as well as the use of DBE in detecting such a complication.