At the end of February 2024, over 11,000 medical residents in South Korea collectively resigned in opposition to the government's policy to increase medical school admissions, raising widespread concerns about potential health consequences amid prolonged workforce shortages in acute hospitals.

To assess the impact of the medical residents' walkout on mortality rates in South Korea during 2024.

We conducted a retrospective observational study using mortality data from Statistics Korea's Vital Statistics (2019–2023) and the Ministry of Interior and Safety's Registration Expiration Statistics (2024). Analyses included crude mortality rates by sex, age, and region; sex- and age-standardized mortality rates; and excess mortality estimations using three modeling approaches with and without COVID-19 fixed effects.

We found no evidence of increased mortality in 2024. During the walkout period (March-December 2024), mortality rates (577.4 per 100,000) and age-standardized mortality rates (approximately 650 and 750 per 100,000 for females and males) showed no increase from pre-walkout levels. Excess mortality estimates were consistently negative or negligibly small (-11,989 to -2831 deaths, 95 % CI) after controlling for COVID-19 effects, with more pronounced negative values during the walkout period (-30,779 to -7767). This pattern persisted across demographic groups and regions.

During a year-long walkout, mortality patterns in South Korea remained stable, consistent with findings from shorter healthcare strikes. Policymakers should establish robust and democratic dialogue for healthcare reforms, while researchers should investigate non-mortality impacts, including healthcare quality, access, and patient experiences, to develop comprehensive workforce policies.