In this paper, we present an empirical investigation to measure the effects of privatization on some selected firms listed on Tehran Stock Exchange. The proposed study of this paper selects eleven relatively big sized Iranian firms whose structures were privatized prior year 2011. The main hypothesis of this survey studies whether there is a meaningful relationship between ownership structure and enterprise value of privatized firms. We collect the necessary information before and after privatization process completed and using a regression model examined the main hypothesis as well as five sub-hypotheses. The results of the survey indicate that the number of major shareholders has been reduced after privatization process accomplished, the number of shares had no impact on firms’ values. In addition, non-board members’ duty had not impact on firms’ value before and after privatization process, institutional investors did not play important role before and after privatization process, and separations played important role on firms’ value before and after privatization occurred