Different companies have various policies and methods which are related to instances such as the arrangement of organization structure, the method of operation accomplishment and financial and management reporting that is in accordance with their goals. In addition to macroeconomic sources, conservativeness of each company can be depended on efficiency and proficiency of these policies and methods. Since methods of conducting policies form the internal control structure of each company, in this research we investigated the relationship between internal control weaknesses and conservativeness of companies accepted in Tehran stock and securities exchange during 1387 to 1391.  Using statistical method, panel data of statistical sample group consisting of 102 selected companies in a frame of correlation research, and by using multiple linear regression and compound data has been done.

The results of the research show that based on Shina Koomar model the quality of internal control  has a direct positive effect on conditional conservativeness. Also results of the research in the above model predicate that there is a direct effect of control variable of the ratio of market value of share holders salary to account book salary of share holders on conditional conservativeness, and also predicates reversed effect of company size and pure profit ratio to the total assets on conditional conservativeness. More over variable of financial lever does not have significant effect on conditional conservativeness in the mentioned model.