Abstract
The SENTINEL influenza surveillance system is an important tool for monitoring influenza in Poland. Data from this system are necessary to determine the dynamics of seasonal infections and to announce the epidemic by the country level. For the 2017/18 epidemic season, the dominance of influenza type B was recorded and the highest percentage of infections was recorded in the age group 45-64 years. Among the subtypes of influenza type A, A/H1N1/pdm09 was the predominated subtype. Most cases were reported in the age group of 26-44 and 0-4 years. The influenza virus frequently undergoes modifications. Therefore, it is necessary to constantly monitor the emerging strains around the world.