This study aims to investigate the impact of corporate social responsibility on the relationship between the disclosure of the cost of research and development (R & D) and stock returns of listed companies in Tehran Stock Exchange. Information needed for the study has been collected through financial statements and reports of boards of the 88 companies for the period 2009-2015. For the measurement of disclosure of the cost of research and development (R & D) and social responsibility, we utilized content analysis of board reports. Results of statistical analysis show that the disclosure of the cost of research and development is associated with stock returns. Furthermore, the findings indicated that social responsibility strengthens the relationship between disclosure of the cost of research and development (R & D) and stock returns.