Introduction: Emergency medical systems, as the first line of management of infectious patients, were affected by the 2019 coronavirus acute respiratory disease (COVID-19) pandemic. The aim of the study was to analyze the impact of the COVID-19 pandemic on the Emergency Medical Service (EMS) with emphasis on response time. Material and methods: Retrospective analysis of dispatch card from EMS in Bydgoszcz between January 2018 and December 2020. The differences regarding the EMS response were analyzed between the pre-pandemic (2018-2019) and the pandemic (2020) period in three time-points: from call to Emergency Medical Team (EMT) departure (T1), from departure to arrival at the scene (T2), and from arrival to reaching the emergency department (T3). Results: There were 47783 EMT departures in 2018, 47113 in 2019 and 40835 in 2020. In 2020 mean (SD) monthly number of interventions was significantly lower [3403 (349) vs. 3954 (182), p < 0.001) compared to the 2018-2019 period. During the pandemic period the mean T1 [0.9 (1.49) vs. 0.63 (1.12) min, p < 0.001], T2 [9.91 (6.33) vs. 8.25 (5.07) min, p < 0.001], and T3 interval [40.45 (19.84) vs. 36.56 (14.63) min, p < 0.001] were prolonged in comparison to the pre-pandemic period. The differences in response time were the largest in October-December.Conclusions: During the first year of the pandemic, the number of EMT interventions decreased and the response time was prolonged compared to the pre-pandemic period. The largest differences were observed at the end of the year, which overlapped with the peak of the second wave of COVID-19 infections in Poland.