Abstract Background In the chain of survival for Out-of-hospital cardiac arrest (OHCA), each component of care contributes to improve the prognosis of the patient with OHCA. The SARS-CoV-2 (COVID-19) pandemic potentially affected each part of care in the chain of survival. The aim of this study was to compare prehospital care, in-hospital treatment, and outcomes among OHCA patients before and after the COVID-19 pandemic. Methods We analyzed data from a multicenter prospective study in Kanto area, Japan, named SOS-KANTO 2017. We enrolled patients who registered during the pre-pandemic period (September 2019 to December 2019) and the post-pandemic period (June 2020 to March 2021). The main outcome measures were 30-day mortality and the proportion of favorable outcomes at 1 month, and secondary outcome measures were changes in prehospital and in-hospital treatments between the pre- and post-pandemic periods. Results There were 2015 patients in the pre-pandemic group, and 5023 in the post-pandemic group. The proportion of advanced airway management by emergency medical service (EMS) increased (p