The author presents a hypothesis that the complex of endocrine and metabolic disturbances arising long before the development of endometrial carcinoma determines the biological peculiarities of the tumor, its clinical course, and the prognosis of the disease. On the basis of a prospective study of 366 patients with endometrial carcinoma, the author postulates that there are two different pathogenetic types of endometrial carcinoma. The first pathogenetic type of the disease arises in women with obesity, hyperlipidemia, and signs of hyperestrogenism: anovulatory uterine bleeding, infertility, late onset of the menopause, and hyperplasia of the stroma of the ovaries and endometrium. The second pathogenetic type of the disease arises in women who have no signs stated above or these signs are not clearly defined. The frequency of the first pathogenetic type in the studied group of women was 65%, whereas the frequency of the second type was 35%. The peculiarities outlined above which are characteristic of the first pathogenetic type of the disease determine the development of highly and moderately differentiated tumors (82.3% G1 and G2), superficial invasion of the myometrium (69.4%), high sensitivity to progestogens (80.2%), and favorable prognosis (85.6% 5-year survival rate). In patients who have the second pathogenetic type of endometrial cancer when endocrine and metabolic disturbances are absent or occult, poorly differentiated tumors arise (62.5% G3), a tendency to deep invasion of tumor into the myometrium is observed (65.7%); high frequency of metastatic spread into the pelvic lymph nodes (27.8%); decrease of sensitivity to progestogens (42.5%); and doubtful prognosis (58.8% 5-year survival rate) are noted.