The study of external respiratory function (ERF) is important in the diagnosis of respiratory tract abnormalities in various diseases. In children, especially at an early age, there are many difficulties in conducting studies. In recent decades, due to the development of computer technology, there is great interest in the study of respiratory sounds, methods of their registration, processing and use in the assessment of the respiratory system in children and adults. Russian scientists have developed the method of respiratory airway sound investigation, which has proved its effectiveness, reliability and necessity of use in practice. Computer bronchophonography is based on the analysis of time and frequency characteristics of the spectrum of respiratory noises, arising from changes in the bronchial diameter due to increase in the stiffness of their walls or decrease in the inner diameter. Computed bronchophonography may be used for diagnostics of EFD disorders in patients of all age groups both in the in-patient and out-patient treatment.