OBJECTIVE. The aim of this study was to summarize the epidemiological situation of infectious diseases in Poland in 2023. The ongoing impact of the COVID-19 pandemic and the effects of the influx of refugees to Ukraine were taken into account. MATERIAL AND METHODS. We performed a narrative review of studies published in Epidemiological Chronicle, along with data from the national infectious disease registry, Epibaza, which collects data from epidemiological investigations conducted by the State Sanitary Inspectorate. Mortality data were obtained from reports of the Statistics Poland Office. RESULTS. In 2023, 381,244 cases of COVID-19 and 4,329 deaths due to this disease were recorded. The COVID-19 mortality rate in 2023 was several times lower than in 2022, although COVID-19 still accounted for more deaths than other infectious diseases. An "immunity gap" effect was observed following the COVID-19 pandemic, resulting in a significant increase in the incidence of pertussis (2.5 times compared to 2022), influenza and influenza-like illnesses, and intestinal infections (enteric salmonellosis +57.9%, campylobacteriosis +64.1%, yersiniosis +74.5%, norovirus +27.8%). A reduction in the incidence was observed for rotavirus infections, for which routine infant vaccinations were introduced in 2021. The increase in pneumococcal disease incidence occurred mainly in the adult and senior population. While the number of new HIV diagnoses among Polish nationals is increasing, the number of cases among migrants has declined, although they still account for 25% of all new diagnoses. The incidence of other sexually transmitted infections also continues to increase (compared to 2022, gonorrhoea +110.6%, syphilis +89.6%). CONCLUSIONS. For many diseases, incidence increased compared to previous years, for a variety of reasons, including the persistent "immunity gap" following the pandemic and the specific nature of the vaccination program. The impact of the influx of refugees from Ukraine was minor.