Despite the variety of chronic tonsillitis clinical symptoms, none of the known signs of this disease is typical for it. Purpose of study is development of a method for differential diagnosis of complicated (toxic-allergic) and uncomplicated (simple) forms of chronic tonsillitis. Methods. 147 patients were divided into 2 groups: 1) 61 (42%) — with a simple form and 2) 86 (58%) — with a toxic-allergic form of chronic tonsillitis of the II degree. Patients underwent ultrasound examination of regional lymph nodes, to determine their localization, quantity (single, multiple), shape, size and structure. Results. According to ultrasound data, it was revealed that for the simple form of chronic tonsillitis the following characteristics of the lymph nodes were typical — bean-like form, single, clear contours, homogeneous central parts and reduced vascularization; for the toxic-allergic form of chronic tonsillitis, the following characteristics of lymph nodes were revealed — oval shape, lymph nodes conglomerates, hypoechoic central parts, increased vascularization and irregular shape of the gates. Conclusion. The proposed method allows to quickly and efficiently conduct differential diagnosis of chronic tonsillitis. This technique is easily reproducible in the conditions of any (outpatient, inpatient) medical facility using standard equipment for ultrasound examination, does not require the use of any drugs.