Carcinomas of the endometrium are the most frequent neoplasias of the female genital tract. Precancerous lesions of the endometrium, including simple hyperplasia with and without atypism, complex hyperplasias as well as atypical complex hyperplasias occur 4.5 times more. The existence of hyperplastic or precancerous lesions of the endometrium is well established, but differences in terminology and difficulties in interpretation have complicated the communication between morphologists and clinicians. The risk of a metachronous endometrial carcinoma increases from about 1% in simple hyperplasia to 29-45% in atypical complex hyperplasia. Therapeutic procedures include the gestagen-therapy, depending from age and reproductive status of the women. Atypical complex hyperplasia requires the hysterectomy with bilateral salpingo-oophorectomy to treat a possible simultaneous carcinoma. Transvaginal sonography, hysteroscopy and pulsed Doppler sonography give additional informations and allows to distinguish a pathological from a normal endometrium. These methods may reduce the number of unnecessary diagnostic dilatation and curettage procedures, especially in patients with additionally cardio-vascular and other risk factors. But the histological examination of curettage material is still the "gold standard" for distinguishing between a normal and a pathologic endometrium. The classification and histologic criterias of precancerous lesions of the endometrium is presented and the need for better communication between pathologists and gynecologists is emphasised.