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.