Hossein Mansouri - Department of Accounting, Faculty of Management and Accounting, Tehran South Branch, Islamic Azad University, Tehran, Iran

In capital markets, several factors are used by investors to evaluate the value of the firms. One of these factors in dynamic markets is the existence of mechanisms of corporate governance that tries to defend and protect the rights of beneficiaries. Accordingly, in this study, the researchers sought to examine the relationship between corporate governance mechanisms (Board of Directors’ size) and return on equity in 92 companies listed in Tehran Stock Exchange for the period from 2004 to 2013. The results show that the mechanism of corporate governance (board size) does not affect the efficiency of enterprises listed on the Stock Exchange and this mechanism cannot modify opportunist behavior of managers to use earnings management and increase values. This means that a larger board size is not able to improve the quality of financial reporting through the adjustment of accruals as well as increasing shareholder value by improving efficiency

Corporate governance mechanisms, Board of Directors’ size, return on equity