The objective: of the study was to investigate the indicators of ovarian reserve in infertile women of reproductive age with non-operated ovarian endometriomas more than 3 cm in diameter. Patients and methods. It were examined 63 patients of reproductive age with ovarian endometriosis, including 33 with unilateral ones and 30 with bilateral. The control group consisted of 30 conditionally somatically healthy women of reproductive age with secondary tubal infertility, with regular ovulatory menstrual cycle. All the women were operated on. Prior to the surgery it were studied biochemical and sonographic markers of ovarian reserve, and after pathological study of operational materials – histological markers. Results. It was registered decrease in biochemical, ultrasonographic and histological indicators of ovarian reserve compared to control. Conclusion. The authors conclude that endometriosis directly affects ovarian reserve and ovarian reserve should be assessed not only after it, but before surgery in women with endometriomas and reproductive disorders. It is important to determine the tactics of their management. Key words: endometrioma, ovary, ovarian reserve, operation, Anti-Mьllerian hormone, inhibin B, FSH, estradiol, the number of antral follicles.