Background. Chronic tonsillitis is the most common disease among children and adolescents in the structure of pathology of the ENT organs. Untimely diagnosis and irrational treatment lead to decompensation of chronic tonsillitis and the development of lesions of many organs and systems of the child’s body of tonsillogenic origin. The aim of the work was to study the clinical features and ultrasound changes of the palatine tonsils in adolescents with chronic tonsillitis. Materials and methods. We have examined 47 children aged 13 to 17 years suffering from chronic tonsillitis: group I — 27 patients with compensated chronic tonsillitis, group II — 20 patients suffering from decompensated chronic tonsillitis. The control group consisted of 16 practically healthy children, representative in terms of age and gender. We used clinical methods, ultrasonography of the palatine tonsils, and statistical methods. The study was approved by the Institutional Bioethics Committee and it conforms to the principles outlined in the Declaration of Helsinki. Results. According to the results of an ultrasound examination of the palatine tonsils in children with chronic tonsillitis, the main changes were an increase in their transverse dimensions by more than 15 mm, deepening of lacunae, thickening of the capsule, fibrous changes. In addition, in patients with tonsillogenic lesions of the cardiovascular system and a decompensated form of chronic tonsillitis, the pathological signs of the disease according to ultrasound were more significant and were manifested by unclear contours, increased echogenicity, heterogeneous hyperechoic structure, diffuse fibrous and cystic changes of the palatine tonsils. Conclusions. Ultrasonography of the palatine tonsils is a non-invasive, painless, accessible and informative method for studying the structure of the tonsils in normal and pathological conditions. It allows for a more thorough assessment of their changes in compensated and decompensated forms of chronic tonsillitis.