We report a case of multifocal liposarcoma that showed rapid growth in a short term. A 65-year-old male was referred from a local doctor to our clinic with the chief complaint of abdominal fullness. Abdominal CT shows two huge tumors in the intraperitoneal and retroperitoneal space, and we diagnosed it as multifocal liposarcoma. Both tumors were resected. The surgical specimens of intraperitoneal and retroperitoneal masses were 20 x 10 cm and 12 x 8 cm in size, and 3.5 kg and 2.8 kg in weight, respectively. Histological diagnosis of both tumors was myxoid liposarcoma. However, the tumor recurred 4 months later, and two additional operations were required because of rapid growth. The patient died at 7 months after the first admission. The clinical outcome of myxoid liposarcoma is known to be better than other histological types, but it is very poor when the tumor appears multifocally.