Immunoenzyme assay (non-direct ELISA) was used for analysis of sera from children (age: 4-14 years) with chronic bronchopulmonary diseases. Antibodies to adenoviruses were revealed in 46% of sera as well as a 3-5 time increase of specific antibodies in 50% of cases. Peroxidase-labelled protein A staphylococcus aureus was effective for detection of immune complexes.