A cell line designated HTLS was established from the retroperitoneal liposarcoma. The HTLS line showed stable proliferation without interruption for 2 years and subcultivated over 35 times. The cells were elongated fibrous and spindle in shape, and neoplastic and pleomorphic features. The multinucleated giant cells with fine cytoplasm were seen. The cells proliferated slowly and the population doubling time was about 90 hours. The chromosome number showed a wide distribution of aneuploidy, the mode was hyperdiploid range (51-52), and many marker chromosomes were observed. The cells were transplantable into the submucosa of immunesuppressed hamster's cheek pouch and produced liposarcoma, while were not transplantable into subcutis of nude mice