A malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma in adults. About 70% of tumors arise from the soft tissue of the extremities with only 12~14% of the tumors occur in the retroperitoneum. The clinical characteristics of this tumor consist of an abdominal mass, tendency for local recurrence, paraneoplastic syndrome and a poor prognosis. A 51-year-old woman was admitted to St. Vincent's Hospital with complaining of fever and an abdominal mass. Ultrasound and computed tomography revealed a huge, heterogenous mass in the lesser sac area. The patient underwent an extensive mass resection with a histologic examination revealing a MFH which was positive for alpha1- antitrypsin. We report a case of MFH presenting in the lesser sac with a review of the literatures.