This study aims to contribute to the relevant accounting, corporate governance, and corporate social responsibility (CSR) literature by examining the value relevance of mandatory CSR disclosures in China. Using a difference-in-differences (DID) research design and a sample based on propensity score matching (PSM) over the period from 2003 to 2020, our findings suggest that mandatory CSR disclosures are negatively associated with firm’ values. We also find that firms with a high level of institutional ownership and leverage experience a relatively lower drop in firms’ values as a result of the mandatory CSR disclosures. These findings remain robust to alternative sampling design, use of market to book value as an alternative measure of firms’ market-based performance, and a parallel test to validate our DID analysis. Our findings have useful implications for managers, regulators, policy makers and other stakeholders.