BACKGROUND: Declining cardiovascular mortality rates have been well-documented, yet temporal trends of sudden cardiac death (SCD) in young individuals remain unclear. We provide contemporary nationwide estimates of the temporal trends of SCD in young individuals (1–35 years of age) from 2000 through 2019 and correlate these trends to changes in out-of-hospital cardiac arrest (OHCA) patterns, rates of inherited cardiac diseases, and implantations of implantable cardioverter defibrillators (ICD). METHODS: All individuals between 1 and 35 years of age living in Denmark from 2000 through 2019 were included, with annual re-evaluation of the at-risk population in regard to age. Adjudication of SCD cases relied on multiple sources, including death certificates, medical files, and autopsy reports. Information on OHCA, diagnostic rates, and ICD implantations were captured from nationwide administrative registries. Annual incidence rates of SCD were calculated, and temporal trends in SCD inciden