The epidemiology of infectious diseases was highly impacted by the COVID-19 pandemic. There were 1,306,983 cases notified in 2020 and 41,451 deaths attributed to COVID-19 (according to Statistics Poland). The reported incidence of other infections decreased by 10-98%. We noted especially high decreases in the incidence of viral gastrointestinal infections (by over 70%). The incidence of influenza and influenza-like infections decreased by 34% and tuberculosis by 36% as compared to 2019. However, important decreases were also noted for other diseases under surveillance, which could point to disruption of diagnosis services and reporting due to lockdowns and high workload on the public health services.