The purpose of this study was to determine the effect of conditional conservatism in debt contracts and agency costs on the Tehran Stock Exchange. Debt contracts are meant to measure the five criteria, the debt-to-equity ratio, the ratio of short-term debt to assets ratio, long term debt to assets ratio, debt to asset ratio of non-interest-bearing liabilities Interest assets and to measure the agency costs of free cash flow and the interaction between growth opportunities and to measure the conservative wing models Shiva Kumar (2005) is used. This study applied research and its methods of causal - after the event. Statistical society research Companies including accepted in Tehran stock exchange and research sample with the use of systematic sampling is omissive and conditions research variables the number of 75 companies from 18 industry in the years 1385 to 1390 has been selected.For analysis data and theory test the Statistical technique of diagnosing a picture has been used and the results of that research indicates that compared to the rights of the owners of the debt stock increased the conservatism and lack of effect on Agency costs analysis debts in the form of short and long term will lead to the increase in conservatism and Agency costs are also debts interest resulted in decrease in a conservatism and the Agency costs And debts without interest cost will decrease the Agency costs and the lack of effect on conservatism..