Auditing conforming auditing standards is designed to make a rational confidence for not being material errors and misstatements in financial statements. We test the effectiveness of audit process in detecting material errors and misstatements in financial statements and this article shows the results of this research. In this research, we considered detecting material misstatements resulting of errors in accounting estimates and irregularities. So, we examined all companies listed in the Tehran Stock Exchange and separated the companies that amount of errors and misstatements in their financial statements were material (recorded in prior period adjustments item). Finally, we examined independent audit report about previous fiscal year for the purpose of determining detection or not detection material misstatements by independent auditor, in other words, the effectiveness of audit process in detecting material misstatements.Our result showed that auditing process is effective about detecting material errors and misstatements in accounting estimates and irregularities. Also, there is significant difference between amounts of errors and misstatements in financial statements and detected amounts by auditors. It means, presented amounts by auditors were mostly less than misstatements.