This study of the effect of corporate social responsibility, corporate governance, andcode of conduct on corporate return on operations of the companies listed in theStock Exchange of Thailand has three objectives, 1) to study the practice and thelevel of importance of corporate social responsibility, corporate governance, and codeof conduct of the companies listed in the Stock Exchange of Thailand, 2) to study therelationship between corporate social responsibility, corporate governance, and codeof conduct of the companies listed in the Stock Exchange of Thailand, 3) to study theeffect of corporate social responsibility, corporate governance, and code of conducton corporate return on operations of the companies listed in the Stock Exchange ofThailand. The sample is 118 companies listed in the Stock Exchange of Thailand.The results are: 1. Sixty percent of the sample fully implement all corporate socialresponsibility, corporate governance, and code of conduct. The most important is codeof conduct, followed by corporate governance and corporate social responsibilityin that order, 2. Corporate social responsibility is linked to the code of conduct, andtogether they are linked to the code of conduct and, 3. Corporate social responsibility affects the return on equity in 2006; Code of conduct through supporting socialactivities effects the return on equity in 2006 and economic value added in 2006 and2007. In addition, code of conduct of risk reduction affects the economic value addedin 2006 and 2007.