Our business and professional world has led to competition in the production and distribution; this in turn has led to complexity in financial statements and ultimately to the conflict of interests among the beneficiaries. In the meantime, the role of auditing has as a control mechanism for removing non-certainties become more prominent. In this research, we have studied the relationship between competition in the product market and the audit of 122 active companies listed in Tehran Stock Exchange in the period between 2011 and 2016. Research background has been collected through library studies and data required are also available from the codall sites, www.rdis.ir, www.tse.ir, www.tse.tmc.com; software of Rahavard Nowin and Dadepardaz were used occasionally and the statistical software Ewiews was applied for analysis. Finally, the results of the studies showed that there is a significant and reverse relationship between the competition in the industry and the audit fee of the companies listed in the Tehran Stock Exchange.
