[en] The prognosis of uterine carcinosarcoma is generally poor, its detection rates by cytological and histopathological tests are usually low, and authors have pointed out the usefulness of MRI identification as in the title. The purpose of the present paper is to arrange and confirm the identification method above prospectively. MRI and histopathological diagnoses of patients were compared on uterine mesenchymal (309 cases) and epithelial-mesenchymal mixed (7 cases) tumors. MRI equipments used were Toshiba FLEXART 0.5T and Philips CYROSCAN Intera 1.5T. Fast spin echo method was used for T2-enhaced imaging, and dynamic MRI was performed 25-120 sec after rapid intravenous injection of the gadolinium-contrasting agent. It was confirmed that those tumors giving weak to intense signals heterogeneously in their inner parts in T2-enhanced image, and giving the effective contrasting in dynamic one, are highly possible to be uterine carcinosarcoma. (T.I.)