Purpose-The purpose of this paper is to examine the extent and nature of the corporate social reporting (CSR) practices of the 40 largest Thai companies over the years 1997, 1999 and 2001. Design/methodology/approach-The extent and nature of CSR in annual reports was measured according to the number of words disclosed and trends were analyzed over this five-year period. CSR disclosure was classified according to five key themes, the nature of the evidence, and the type of news disclosed. Findings-The research showed, in aggregate, a trend of increasing amounts of corporate social disclosure, although the five-year trends varied within different industries. CSR among Thai companies was found to be primarily focused on human resources, providing "declarative" good news disclosures. Legitimacy theory, political economy theory and economic conditions were used to present explanations for the trends. The study concluded that while no single perspective can explain the disclosure of CSR, the empirical findings demonstrate that the key areas of company social exposure are reflected by CSR. Originality/value-This paper makes an important contribution to the knowledge of CSR in Asia and demonstrates similar issues in CSR reporting to those found in other countries.