Background. Chronic endometritis and endometriosis have a lot in common. Both diseases are long-term inflammatory processes, with definitively unspecified etiological factors and pathogenetic mechanisms that negatively affect fertility and may cause pelvic pain or abnormal uterine bleeding. The issue of effective and timely diagnosis of chronic endometritis remains open due to the lack of specific clinical symptoms and clinical examination data. Assessment of current scientific evidence of the interrelationship between endometriosis and chronic endometritis. Materials and methods. A systematic search of scientific medical information has been conducted in English-language databases: MEDLINE, Scopus, Web of Science, Medline, The Cochrane Library, PubMed. Results. According to the review of various scientific studies that have recently been conducted, it has been found that patients with endometriosis statistically have a significantly higher risk of developing chronic endometritis by 1.3-2.5 times than women without endometriosis. Using a histological endometrial study and detection of CD138, chronic endometritis was found in 52.94 % of women in the endometriosis group and in 27.02 % of patients in the endometriosis-free group; the rate was significantly higher in the endometriosis group than in the control group (p = 0.0311). Moreover, 76% of women with endometriosis showed inflammatory processes of pelvic organs (compared to the control group, where inflammation was found in 38.4 % of women, p < 0.0001). Conclusions. Patients with endometritis demonstrate a positive correlation with development of endometriosis. Given the inability to establish a causal relationship between endometriosis and chronic endometritis, extended diagnosis is necessary to eliminate chronic endometritis, especially if women have abnormal uterine bleeding or chronic pelvic pain. The combination of histological and immunohistochemical endometrial examination methods has shown its effectiveness in timely diagnosis of chronic endometritis. Identifying and adequately treating this condition will help avoid unnecessary surgery.