Despite a large number of existing conservative, minimally invasive treatment regimens and procedures for acute bacterial rhinosinusitis in children, the incidence of the disease is not only not decreasing, but rather increasing. Low-frequency ultrasound is legally considered to be one of the current highly efficient physical methods. But constructive solutions to this issue are still not fully implemented; the technological process of applying a low-frequency ultrasound in children with acute bacterial rhinosinusitis is not disclosed in the context of current criteria for evidence-based medicine. Objective. To enhance the efficiency of low-frequency ultrasound treatment in children with acute bacterial rhinosinusitis. Patients and methods. The investigation enrolled 109 patients aged 5 to 17 years with acute bacterial rhinosinutitis. Their examination included history data collection (using a SNOT-20 questionnaire), analysis of patients’ complaints, objective examination, instrumental (nasal cavity endoscopy, sinonasal computed tomography) and laboratory (general blood analysis, determination of immunoglobulins A, M and E, cytological examination of nasal discharge, microbiological study of middle meatus discharge) studies, as well as estimation of mucociliary transport time (using the saccharin test). All the patients were additionally examined by a pediatrician. They were divided into 2 groups: a study group and a comparison group. The study group was treated with low-frequency ultrasound; the comparison group received combination treatment with nasal irrigation by conventional methods. Results. There was a statistically significant difference in the levels of immunoglobulins A and M in the study and comparison groups just on day 3 of treatment. The concentration of immunoglobulin A in the study group was 1.71 g/l after day 3 of therapy (4.20 g/l on day 1; p<0.001); the comparison group showed a less noticeable decrease from 4.33 g/l on day 1 of therapy to 2.83 g/l after 3 days of treatment (p<0.001). On 3 day of therapy, the most pronounced effect was observed in the study group according to the following criteria: body temperature, total leukocyte count, number of neutrophils, and the levels of immunoglobulins A and M in the general blood analysis. Conclusion. The findings indicate that the use of low-frequency ultrasound to treat in children with acute bacterial rhinosinusitis causes positive changes just on day 3 of treatment.