Currently, the diagnosis of chronic bronchitis as an independent nosological form in children is being improved. This direction provides for the differentiation of chronic bronchitis from other bronchopulmonary diseases occurring with bronchitis syndrome. It is known that chronic bronchitis is a constant companion of bronchiectasis, primary ciliary dyskinesia and its main form - Kartagener's syndrome, and is also one of the manifestations of cystic fibrosis. The viciousness of the development of the bronchopulmonary system (aplasia, hypoplasia of the lungs, Mounier-Kuhn syndrome, Williams-Campbell syndrome, polycystic lung disease, bronchial branching anomalies), as a rule, predisposes to the formation of chronic bronchitis.