Objective — to assess the ovarian reserve in women of reproductive age with endometrioma before and after surgery. Material and methods. A prospective study. Setting — department of operative gynecology. Patients or Participants — 136 women of reproductive age with endometriomas. Interventions — USI with measurement number of antral follicles, evaluation of AMH levels were conducted before, 3 and 6 months after surgery (laparoscopic removal of the the cyst). Results. Patients were divided before surgery: I group (n=87) — with normal ovarian reserve and II group (n=49) — with low ovarian reserve (Bologna criteria). Prior to surgery, there were significant differences between the groups in the level of AMH (4.02±2.24 and 0.78±0.32 ng/ml in I and II groups, respectively, p<0.01), the level of FSH (5.36±2.41 and 9.15±3.06 ME/l in I and II groups, respectively, p<0.01). The number of antral follicles less than 5 in the I group was in 13.8% of cases, in the II group — in 57,1%; p<0.05. Statistically significant risk factors for low ovarian reserve before surgery were: age >30 years, previous ovarian surgery, recurrence of endometriomas, bilateral involvement of the ovaries, 3—4 stage of the endometriosis (p<0.05). In the postoperative period the level of AMH decreased in all patients. 3 months after surgery, the average serum AMH level was 2.57±1.83 and 0.40±0.29 ng/ml, in 6 months — 2.44±1.79 and 0.67±0.36 ng/ml in group I and group II, respectively. In the postoperative period the number of antral follicles less than 5 was found in 28.7% of cases in group I and 83.7% in group II. 19.5% of women had a low ovarian reserve in group I at 3 months after surgery, and 20.7% in 6 months. Low ovarian reserve in the postoperative period was associated with: bilateral resection and the size the endometrioma more than 4 cm. Conclusion. Preoperative examination of patients with endometriomas and individual management tactics taking into account the risk factors of ovarian reserve reduction is essential.