Malignant fibrous histiocytoma (MFH) is a soft-tissue sarcoma originating from fibroblast cells, characterized by a high rate of metastasis or recurrence. This tumor rarely develops in the gastrointestinal tract, with no more than 30 cases described in the literature. We report a case of MFH of the abdominal cavity in a 45-year-old woman who presented with epigastric pain, anorexia, and weight loss. A computed tomography (CT) scan of the abdomen revealed multiple solid tumors in the peritoneal cavity. We performed exploratory laparotomy and found at least 15 solid whitish tumors attached to the wall of the small intestine, as well as to the parietal peritoneum. There were three metastases in the liver. All of the tumors were excised, most of which were about 10 cm in diameter. Histopathological findings indicated a stromal tumor consisting of spindle cells, and immunohistochemical examination of the resected specimens established the definite diagnosis of a pleomorphic MFH. The patient had an uneventful postoperative course and was given adjuvant chemotherapy. She is currently well 2 years after her operation. We review the clinical picture of this tumor in the abdominal cavity, and discuss its diagnosis, pathogenesis, and treatment.