Twenty-nine cases of liposarcomas were examined by CT; in 60% of them the CT finding was that of an ill defined, often large mass with content uniformly dishomogeneous and CT numbers ranging from -40 to +28 H.U. Diagnosis of liposarcoma is often possible when this finding is recognized in a mass of the thigh or retroperitoneum where these tumors frequently arise. Authors report differential diagnosis between liposarcomas and other lipomatous tumors such as angiomyolipoma of the kidney (when it is large and only attached to the kidney by an inconspicuous pedicle) and intramuscular lipomas (50% of them are located in the thigh).