Primary natural killer (NK) cell like T cell lymphoma of the terminal ileum is extremely rare. It most frequently occurs in the nasal or paranasal areas and less frequently in the skin, the soft tissue, and the gastrointestinal tract. NK/T cell lymphoma involving gastrointestinal tract has characteristic endoscopic features of Inflammatory bowel disease. We herein describe a first case of primary NK/T cell lymphoma misdiagnosed as Behcet's enteritis of the terminal ileum colonoscopically and complicated by cecal bleeding and perforation.