26985 and 459 young subjects of Uzbek nationality underwent preventive and inpatient examination to specify clinical characteristics of chronic nonspecific diseases of the lungs. These were characterized by slight subjective symptoms, poor informative value of general clinical tests, pronounced changes in lung ventilation, cytology of bronchoalveolar lavage, bronchologic and immunologic parameters. It is evident that Uzbek adolescents and youths suffering from chronic nonspecific pulmonary diseases develop homeostatic disorders. This contradicts the established views on young age as most favourable biologically and for maximal adaptation.