A case is reported of malignant mixed mesodermal tumor of the uterus in a postmenopausal 56 year-old woman presenting vaginal bleeding and who was cytologically diagnosed with an endometrial aspirate. The cytologic examination of smears showed the presence of two different cellular types: adenocarcinomatous and sarcomatous (some with evident cross striations). The patient underwent total hysterectomy with lymphadenectomy. Histologically, a malignant mixed M\ufcllerian tumor was confirmed. Cytological, histological, histochemical and immunohistochemical features are described in detail together with the main differential diagnosis