This research examines the effect of corporate governance on firm s value. The research has been carried out on the food industry of companies listed in the Tehran Stock Exchange (TSE) which is a major contributor to Iran s Exports for five years from 2007 to 2011. There are several aspects and dimensions of corporate governance, which may influence a firm s value but this study focused on four aspects namely Ownership Concentration (OWNCON), Institutional Ownership (INOWN), Chief Executive Officer Duality (CEO) and Board s Independence (BOIN). Firm s value has been measured through Tobin s Q. Strong and positive impact of corporate governance on firm s value has been seen.