The study of the effect of corporate social responsibility, corporate governance, and code of conducts on corporate return on operations of the companies listed in the Stock Exchange of Thailand has the objectives 1) to study the practice and the level of importance of corporate social responsibility, corporate governance, and code of conducts of the companies listed in the Stock Exchange of Thailand 2) to study the relationship between corporate social responsibility, corporate governance, and code of conducts of the companies listed in the Stock Exchange of Thailand 3) to study the effect of corporate social responsibility, corporate governance, and code of conducts on corporate return on operations of the companies listed in the Stock Exchange of Thailand. The sample is 118 of the companies listed in the Stock Exchange of Thailand. The results are:1. 60% of sample conducts all of corporate social responsibility, corporate governance, and code of conducts. The most importance is code of conducts, corporate governance, and corporate social responsibility consecutively.2. Corporate social responsibility has the relationship with code of conducts and corporate governance has the relationship with code of conducts.3. Corporate social responsibility affects on return on equity in 2006. Code of conducts of social supporting affects on return on equity in 2006 and economic value added in 2006 and 2007 and code of conducts of risk reduction affects on economic value added in 2006 and 2007.