The purpose of the study was to find out the frequency of occurrence and the role of Chlamydia infection in the pathogenesis of acquired subglottic stenosis in children. Forty-nine patients of the age from 1 year 10 months to 15 years with acquired cicatricial laryngotracheal stenosis were examined. The immunofluorescent method was used to detect serum antibodies to the antigens of Chlamydia trachomatis and Chlamydia pneumoniae. Dilutions of 1:32 for C. trachomatis and 1:64 for C. pneumoniae were considered positive. The results of the study suggested both a high frequency (26.5%) of Chlamydia infection (C. pneumoniae) of the children with acquired subglottic stenosis, as well as 92% of infected children were either with tracheotomies or had been decannulated earlier. It reasonable to test children with a tracheostomy for the presence of Chlamydia infection to perform timely and specific antibiotic therapy.