We report a case of postoperative recurrence of liposarcoma of the mesenterium successfully treated by chemotherapy using ifosfamide (IFM) and cisplatin (CDDP). A 58-year-old man presented with a strange feeling in the lower abdomen. Enhanced computed tomography showed enhanced non-epithelial tumor in the pelvic space. The tumor moved on palpation, so we diagnosed liposarcoma from the mesenterium, and resected the tumor on 22 August, 2002. The pleomorphic liposarcoma was 11 x 14 x 7 cm, growing from the mesenterium of the sigmoid colon, and weighed 640 g. We performed re-operation due to pelvic recurrence on 24 March, 2003. On 18 September of the same year, when we performed re-operation again for pelvic recurrence, there were so many recurrences on the mesenterium of small intestine that resection was impossible. We started chemotherapy 3 days later using 3.0 g/body IFM from 1 October 2003, together with 1,800 mg/body mesna for prevention of hemorrhage cystitis. We continued chemotherapy using 3.0 g/body/day IFM together with 1, 800 mg/body/day mesna on an outpatient basis, upon his weekly visit to the hospital. Patient remission was shown by abdominal enhanced computed tomography on 10 December. Some grade 2 alopecia and grade 2 leukopenia occurred, so we changed to chemotherapy once every two weeks. Then, it continued to decrease, without any side effects. The response appeared to be complete on computed tomography in August 2004, and we have been continuing the same chemotherapy without recurrence.