This study examines the effect of highly activating corporate social responsibility (CSR) onfirms’ financial reporting policies. For empirical testing, verification on the distinction of accountingconservatism between firms highly activating CSR and not is conducted. Firms highly activatingCSR, in comparison to the opposite, being expected to have less incentives regarding the conservatism,are predicted to less conservative disposition on accounting practice. In order to verify the abovementioned, we measure CSR activities in consideration of inclusion in KEJI Index (top 200 firms)and measure the conservatism by the Ball and Shivakumar (2006) model, targeting the KOSPIlisted firms from 2005 to 2011. As the empirical results, those firms ranked in KEJI Index areless conservative than the opposite. This indicates that the firms highly activating CSR have lowerinternal incentives on the conservative accounting practice and that accounting conservatism isinfluenced on by CSR activities. We also conduct the several rubustness check on the analysisand we find that our results are rubust to these additional analyses. This study investigates the association between excellence in CSR activities and corporateconservative accounting practice and empirically proves to CSR activities’ significant influenceon not only firm value and financial performance but also conservative accounting practice. Therefore, in consideration of laying out distinctive and logical evidence for the CSR activities’role and influence, the results of this study provide insight into the CSR activities related research.