Relevance. The question of the aging of the placenta is of some interest, both for clinicians and morphologists. In this process, there is a significant change in its function, associated with a decrease and even a violation of the processing and delivery of nutrients and oxygen from the mother to the fetus. According to the established opinion, the priority is the involutive-destructive changes. The most common involutive-destructive changes in the placenta include heart attacks and fibrinoid accumulation. At the same time, of course, it is necessary to take into account not only its very presence in this body, but also the increase in its quantitative component. The aim of the study is to determine the signs of pathological aging of the placenta against the background of thyroid diseases in the mother. Materials and methods. The study examined the placenta material of 558 pregnant women, of which the first group included 458 placentas of women suffering from various diseases of the thyroid gland (thyroid gland): 74 women – thyroid pathology with euthyroid condition. The second group included 265 placentas of women with hypothyroidism, including: 114-autoimmune thyroiditis, 107-postoperative hypothyroidism, 23-polyglandular syndrome, 14-congenital hypothyroidism, 7-post-radiation hypothyroidism. The third group consisted of 119 placenta samples from women with hyperthyroidism (DTG) (32-patients with pregnancy due to drug compensation or remission of the underlying disease; 38 - in the presence of a decompensated condition or the onset of the disease, 49 — relapse of DTG). The control group consisted of 100 placentas of women who did not suffer from thyroid pathology. Results and discussion. When studying the vessels of the umbilical cord in thyroid diseases in the mother with euthyroidism, the fullness of the vessels was mainly determined, and in hypo - and hyperthyroidism, the vessels were ischemic, and more in hyperthyroidism. In the placenta, the content of sclerosed altered villi increased in the study groups in the following sequence: euthyroidism (14.2±1.8%), hypothyroidism (17.2±1.3%), hyperthyroidism (22.1±1.5%), which is significantly less than the same indicator of the control group (7.9±1.3%). A similar pattern was determined for fibrinoid – altered villi: 13.6±1.6% (euthyroidism), 14.5±2.1% (hypothyroidism), 19.2±2.4% (DTG), control-8.1±1.4%. The amount of fibrinoid in the villous tree was significantly increased in the group of euthyroidism-33.1±5.7%, compared with the control group – 1.3±0.7% (p