Objective. To evaluate the efficiency of therapy in patients with thin endometrium before in vitro fertilization (IVF) through uterine cavity irrigation with drug solutions exposed to low-frequency ultrasound. Materials and methods. Examinations were made in 46 women with failed IVF attempts and a detected M echo reduction. After the examinations including a sonographic assessment of the thickness and structure of the endometrium and hemodynamics of its vessels, hysteroscopy, and endometrial histological and immunohistochemical studies, the patients received therapy by irrigating the uterine cavity with drug solutions cavitated by low-frequency ultrasound (a total of 3 cycles). At the end of treatment, 42 patients with positive changes in the endometrial thickness underwent IVF. The results were assessed from the changes in the endometrial thickness measured by sonography before and after treatment, from the occurrence of pregnancy conceived by IVF and from its outcomes. Results. Before and after treatment, the endometrial thickness (M echo data) was 5.8±1.1 and 8.7±0.9 mm, respectively. Clinical pregnancy was recorded in 40.5% of the patients who entered the ART protocol after treatment. Of them, full-term delivery occurred in 76.5% of patients; miscarriage was in 5.9%; undeveloped pregnancy was also in 5.9%. At the time of writing this article, 2 (11.8%) patients were still carrying their pregnancies. Conclusion. The use of ultrasonic cavitation in patients with thin endometrium makes it possible to increase the thickness of the endometrium and to restore its structure, to improve the hemodynamic parameters of uterine blood flow, and, it is of utmost importance, to enhance the effectiveness of an IVF program. The pregnancy rate suggests that the solutions cavitated by low-frequency ultrasound are effective in affecting the pathogenesis of chronic endometritis as a cause of infertility.