An inflammatory myo5broblastic tumor (IMT) is a rare tumor in the abdominal cavity. A number of descriptive terms have been used to describe inflammatory tumors with myafibroblastic proliferation, The etiology and the biologic behaviors of IMTs are still unknown. Extensive pathologic examinalion is important to prevent misdiagnosis, and the need for keg- term follow up is emphasized. Recently, we experienced e case of a huge inflammatory myofibroblastic tumor of the abdominal cavity in a young male. The patient had a pain- less mass in the entire abdomen. The resected specimen revealed a 15×14×12 cm3 mass involving the posterior rectus sheath, mesentery, ascending, and descending colon; and omentum. We present our experience with that along with a review of literature. (J Korean Surg Soc 2001;60: 114-117)