This study examines whether household loan delinquency\r\naffects the profitability of Korea’s four major commercial banks before and after COVID-19, using year-end data from 2015 to 2024. The sample comprises KB Kookmin Bank, Shinhan Bank, Hana Bank, and Woori Bank, and profitability is measured by return on assets (ROA) and return on equity (ROE). The key explanatory variable is the household loan delinquency rate, while capital adequacy (CAR), non-performing loans (NPL), operating efficiency (CIR), and liquidity (LDR) are included as CAMELS-based control variables. The empirical results show that bank profitability differs between the pre-COVID and COVID-19 periods for ROE but not for ROA, so the hypothesis of a profitability difference is only partially supported. Household loan delinquency does not have a statistically significant effect on either ROA or ROE. Instead, NPL and CIR emerge as the main determinants of bank profitability, whereas CAR and LDR play only a minor role. The COVID-19 indicator is negative and significant, suggesting that the pandemic reduced profitability, while its interaction with household loan delinquency is insignificant, implying that COVID-19 did not materially change the effect of household loan delinquency. Overall, the findings indicate that, for Korean commercial banks, asset quality and cost efficiency are more important drivers of profitability than household loan delinquency.