Aim. To study relationship between influenza virus infection and activity of clinical presentations of atherosclerosis. Methods and results. Average blood level of IgG to influenza A virus was significantly higher in patients with progressing forms of ischemic heart disease then in patients without objective signs of exacerbation of atherosclerotic process. Mean titles of antibodies to parainfluenza virus and adenoviruses were similar in both groups of patients. Direct detection of viral DNA by polymerase chain reaction was carried out in samples of aortic wall taken during coronary artery bypass surgery with the use of primers for hemagglutinin of H1N1, H3N2 viruses. RNA of influenza virus was found in these samples. Conclusion. The presence of viral RNA in vascular atherosclerotic lesions could be indicative of possible pathogenetic role of influenza infection in progression of clinical course of atherosclerosis.