Influenza A and B viruses cause epidemics every year, with approximately 3-5 million serious cases and about 290,000 to 650,000 deaths worldwide. Most patients die from bacterial complications of influenza. The aim of our study was to describe the clinical pictures of influenza and the development of the complications in seniors over 65 years of age, who were treated in University Hospital Pilsen. The course of the disease and changes in laboratory parameters were evaluated with regard to the method of treatment performed.