Four patients with pathologically proven retroperitoneal liposarcomas were examined by computed tomography. The variable densitiesof liposarcomas were closely correlated with their tissue component. Well differentiated liposarcoma was predominently composedof fat density, where as pleomorphic liposarcomas were of higher densities than fat. Liposarcomas often includedmore than one type of tumor tissue, resulting in masses of different densities coexisting within the same mass. CT scan can probvide informations about the location, size, extent, component of the tumor, relationship with adjacent anatomic structure, the presenceof metastasis, in diagnosing this tumor.