Clinical and morphological analysis of 91 cases of adenomyosis was performed. In our study deep adenomyosis was found to be prevailing. The incidence of stages III and IV of the process was 49,5 % (45 cases) and 14,3 % (13 cases), respectively. Stages I and II were detected in 4,3 % and 31,9 % of cases, respectively. The most common morphofunctional type in adenomyosis stages I-II was stationary form (36,4 %). Expression of vimentin - a marker of mesenchymal differentiation, detected in the epithelial component of endometrioid heterotopias and eutopic endometrium in adenomyosis, suggests pathogenetic role of epithelial and mesenchymal transformation in the development and progression of this disease. Positive expression of vascular endothelial growth factor in the basal layer of the endometrium and endometrial heterotopias confirms the importance and unidirectionality of changes in the foci of adenomyosis and in the basal layer of the endometrium in patients with internal genital endometriosis. Expression of Ki-67, bcl-2, prevalence of proliferative changes in glands of the epithelium and cytogenic stroma cells in heterotopias, high frequency of endometrial hyperplasia demonstrate the importance of proliferation activity and low level of apoptosis in endometrial heterotopias and endometrium in adenomyosis.