This study investigates, first, whether “what the company say” or its corporate social responsibility disclosures(CSRD) reasonably reflects “what the company do” or its corporate social performance(CSP), and second, whether the disclosures are used by market participants as credible non-financial information which complements financial data. To answer these questions, we constructed a new CSRD measure using content analysis. We collected sustainability reports for the period 2009-2014(repoting year basis), and tested the relationships between (1) CSRD and CSP, (2) CSRD and future financial and market performance(CFP), and (3) CSP and CFP. We found that, first, CSRD does not have a significant relationship with CSP proxied by KEJI nor CFP proxied by ROA; second, CSRD failed to influence the markets; none of the relationship between CSRD and Tobin’s Q nor stock price are significant. Tests using pages, the GRI rates, and the 3rd party assurance instead of CSRD, or DJSI and ESG instead of KEJI do not change our conclusions. We interpret our results as a proof that companies do not prepare CSR disclosures honestly, nor the investors consider the reports as reliable information. This paper is the first empirical test which implements content analysis on the sustainability reports in Korea.