Bargaining power is one of the most influence factors on adopting conservative approaches by companies. Conservatism approaches can influence the expectations of future earnings and cash flow. This research attempts to study the relationship between bargaining power and accounting conservatism in Tehran stock exchange during the period from 2003 to 2013. Using systematic sampling method, 115 companies were selected. In order to test data, statistics such as: regression, correlation, F statistic, T statistic and Durbin-Watson statistic were used. Basu model was used to test conservatism and to test bargaining power variables such as comparative advantage and relative concentration were used. According to research findings, there is a meaningful and positive relationship between firms bargaining power and accounting conservatism in Tehran stock exchange. Therefore, through increasing the reliability of income, accounting conservatism can reduce costs related to information asymmetry among different stakeholders. Finally, research findings show the increase of bargaining power - which can be obtained through increasing competition in markets - can improve information flow between firm and stakeholders.
