Background Given that Swedish authorities have been widely viewed as having practiced an unusual approach to the COVID-19 pandemic and given that Sweden is notable for a low incidence of trauma, we wanted to learn how the pandemic may have affected the number of trauma admissions in Sweden. Methods We conducted a retrospective cohort study based on the Swedish trauma registry (Svenska Traumaregistret). The study period was March 1, 2020 to June 30, 2020. As a basis for comparison, the record for the same time during the previous year, 2019 was used. Results During the four months of the first wave of COVID-19, 2020 there was a decline of 24.2% in the total number of trauma patients in Sweden. There was no significant change in 30-day mortality rates, 4.7% 2019 and 5.1% 2020, (p = 0.30). The number of injuries per patient was higher during the pandemic 3.8 injuries 2019 and 4.1 injuries 2020 (p = 0.02). The NISS 6, 2019 and 8, 2020 was higher during the pandemic. Conclusions As a consequence of what were seen by many as all too lenient actions taken to deal with COVID-19 in Sweden during spring 2020, there was still a reduction in trauma admissions most likely due to an adherence to the voluntary recommendations, the reduction was not as prominent as what was seen in many countries with harsher restrictions and lockdowns.