The objective: to study the prevalence of ovarian endometriosis in women of reproductive age, the features of clinical and ultrasound picture of endometriosis. Patients and methods. The study involved 22 patients with endometriomas, the control group – 50 women gynecological and somatically healthy. Results. The incidence of ovarian endometriomas in the structure of benign tumor-like formations of ovaries is 0.62%. In 72.73% of ovarian endometriomas occur on a background of concomitant gynecological pathology. Clinically, in 77.27% of cases there is a pain syndrome, in 59.09% – algomenorrhea, in 13.64% – infertility; 18.18% of cases endometriomas remain «dumb» and proceed with the erased clinical picture. Sonologically in patients with endometriomas adenomyosis, endometrial hyperplasia, changes in the contralateral ovary are determined. Conclusion. Without additional methods of diagnostic gynecological examination may identify the 3 cm tumor-like formation of the ovary with different characteristics, which does not allow to differentiate endometrioma from inflammation, functional and ovarian tumors. Ultrasound can diagnose pathological ovarian formation of 1 cm, detailing the nature of the cyst. Key words: endometriosis, reproductive age, retrospective analysis, ultrasound.