Abstract: This study examined the application of corporate social responsibility by the Saudi companies listed at the stock market. Also, the study aimed to construct a composite index for social responsibility. A descriptive research design was adopted. Corporate Social Responsibility was measured using CSR index which including six activities. Company performance was measured using net income, return on assets and return on equity. Descriptive statistics, t-test, ANOVA regression and correlation analysis were carried out. Descriptive statistics were done to describe the data set of Saudi companies which represents 15 sectors for the year 2015. Findings showed high level of CSR application among Saudi companies listed at stock markets and the performance of CSR towards customers was the highest when compared to the other activities. Significant differences were found between companies regarding CSR performance. The study, however, found no significant relationship between CSR and size and having an independent department for CSR does not affect the application of social responsibility activities. The study recommended that for improving CSR governance in particular, Saudi companies must formalizing governance policies: codes and guidelines and ensuring the sustainability of the business.