Objective: to compare 2D ultrasound and 3D with HDlive mode ultrasound in the diagnosis of endometrial polyps in infertility.Material and methods. The retrospective cohort study included 116 women aged 29 to 43 years (mean age 36.9 ± 3.78) with infertility who were observed at the Nova Clinic Center for Reproduction and Genetics from January 2021 to June 2024. 2D and 3D ultrasounds were performed in all patients. The final conclusion on the presence or absence of pathology was based on the results of the 3D study with HDlive mode. The histological verification of polyps was carried out after hysteroscopy.Results. Hysteroscopy revealed no signs of pathology in 5 (4.3%) patients; moreover, the results of 2D imaging were also negative, and the results of 3D imaging were positive. In other 111 cases (95.7%), the diagnosis of a polyp was confirmed on hysteroscopy. Among them, no signs of pathology were found on 2D ultrasound in 19 (16.4%) patients. According to the obtained results, the use of 3D imaging with HDlive mode leads to overdiagnosis and false positive results with a chance of 4.5%. On the contrary, 2D imaging leads to underdiagnosis and false negative results with a chance of 19.6%, which is statistically significantly higher than the chance of a false positive result using the 3D method (p = 0.008). Thus, the chance of a false result using the 2D mode is 4.4 [1.57; 12.09] times higher than using the 3D mode.Conclusions. The study demonstrated a higher accuracy of the 3D ultrasound compared to 2D ultrasound in diagnosing endometrial polyps.