Introduction. Currently, the application of ultrasonic energy for tissue dissection is a routine practice in surgery. Its effectiveness and safety has been proven in proctology, pediatric coloproctology, surgeries in the endocrine organs and in the abdominal organs.Material and methods. Given the features of the endocrine system, the anatomy of virilized genitalia and positive experience in applying ultrasonic energy for surgical interventions, the authors present a comparative trial on the effectiveness of ultrasonic knife (USK) and traditional electrocoagulation in vaginoplasty in patients with disorders of sex development.Results. The obtained findings demonstrate that USK in comparison to traditional electrocoagulation significantly reduces vaginoplasty duration by 30%: median and quartiles of this index with USK were 57.5 [50; 65] min, while in the electrocoagulation group – 82.5 [75; 90] min. Difference is statistically significant (U-test 83.5, p <0.001) too. Difference between medians and its 95% confidence interval was 25 [20; 35] min.Conclusion. USK has better effects due to less tissue bleeding and, as a consequence, better visualization of the surgical field. An additional advantage is a unique ability to gently mobilize and preserve anatomical structures of the pelvis.