Summary. Background: It is known that more than half of the genes encoding human proteins are regulated by various microRNAs (miRNAs, miR), the expression of which may be associated with various pathological conditions. At the same time, the question of assessing the relationship between the expression of particular miRNAs and the aggressive molecular subtype of endometrial cancer remains open. Aim of the study was to determine the relationship between the expression of miR-34a, miR-125b, miR-142 and miR-101 in endometrioid carcinomas of the endometrium (ECE) and the features of the disease course. Materials and Methods: The samples of surgical material of 51 patients with ECE (mean age 59.8 ± 7.1 years), I–III stage were investigated using morphological, immunohistochemical methods, real time polymerase chain reaction (PCR), cytofluorometry. Results: In endometrial tumors with high proliferation index (> Me), the expression of miR-34a, miR-142 and miR-125b significantly decreased (1.8, 2.7 and 1.5 times, respectively) compared with those in ECE with low proliferation index (< Me). The expression of all studied miRNAs was lower in G3 tumors and those that deeply invaded the myometrium compared to G2 carcinomas and tumors with an invasion of < 1/2 myometrium and significantly decreased in tumors of patients with low stage III compared with stage I–II. The high (> Me) microvessel density in ECE was associated with a significant decrease of miR-125b and miR-101 expression, and the presence of signs of epithelial-mesenchymal transition — with a decreased expression of miR-34a and miR-101. Conclusions: The study revealed a significant heterogeneity of expression of miR-34a, miR-125b, miR-142 and miR-101 in ECE, which is associated with changes in morphofunctional characteristics of endometrial carcinoma.