Benign ovarian tumors (BOT) have a significant impact on fertility and are associated with infertility, which, in turn, relates to endometrial receptivity and depends on the ovarian status, forming the so-called endometriopathy. Objective. To study the morphological and functional features of the endometrium in patients of reproductive age before and after ovary-sparing surgery for BOT according to 2D and 3D ultrasounds. Patients and methods. The study included 145 patients who underwent surgery for BOT. Patients were divided into two groups. Group 1 included 75 patients with diminished ovarian reserve (OR), group 2 included 70 patients with normal OR. Diminished OR was defined as serum Anti-Müllerian hormone (AMH) level <1.1 ng/mL. Pelvic ultrasound (US) was performed in the mid-secretory phase before and 6–12 months after surgery. We measured endometrial thickness, endometrial pattern, visualization of basal and spiral arteries by 2D ultrasound, volume and volumetric blood flow in the endometrial and subendometrial regions by 3D ultrasound. Results. The analysis revealed endometrial dysfunction in patients with diminished OR before and after surgery, however there was a trend towards improvement in all the examined parameters after 12 months. In patients with normal OR before surgery, endometrial parameters did not differ from the population, but more persistent abnormalities were noted in the postoperative period. Conclusion. The 3D ultrasound technique provides an objective assessment of morphological and functional features of the endometrium and allows to identify markers of endometrial dysfunction. Key words: benign ovarian tumors, volumetric blood flow, ovarian reserve, 3D ultrasound, endometrium