The aim of the study was to analyze respiratory viruses and cytokines in induced sputum samples, serum Mycoplasma pneumoniae antigens and antiMycoplasma and antiChlamydia antibodies in stable patients with bronchial asthma and chronic obstructive pulmonary disease (COPD) phenotype. Methods. RNAs of rhinovirus, respiratory syncytial virus, metapneumovirus, types 1, 2, 3, and 4 influenza viruses, coronaviruses ОС43, Е229, NL63, and HKUI; DNA of group B, C and E adenoviruses and bocavirus were detected by realtime PCR with hybridization and fluorescent detection. Serum IgG, IgM and IgA antibodies against C. pneumoniae were detected with indirect microimmunofluorescence assay. Mycoplasma pneumoniae antigens were detected with aggregate hemagglutination method. Results . In patients with asthma plus COPD phenotype, three respiratory viruses were detected in sputum, such as rhinovirus, respiratory syncytial virus and adenovirus; antigens of and / or antibodies against M. pneumoniae and Chlamydia pneumoniae were also detected in blood sera. The respiratory infections were associated with imbalanced ratio of interferon types I, II, III and MxA antiviral protein. In patients with no expression of IFNβ gene, IFNα RNA was detected in 58.3% of samples and IFNλ RNA was detected in 42.9 % of samples. Decreased functional activities of IFNα and IFNγ were found.