摘要:The purpose of this study is investigate the effect of auditor's opinions on shares prices and returns in Tehran Stock Exchange. This study conducted about companies in Tehran Stock Exchange during the period 2002-2008.For to do the investigate opinion classified in two groups, and to be discussed two hypothesis. In this research two test named-Test and Man-Whiteny have been used. Present result of these research shows, in confidence interval 95% there is no significant relationship between auditor's opinion and share prices. Present result of these research shows, in confidence interval 95% there is no significant relationship between auditor's opinion and share returns. Generally the results of this study shows, the both of hypothesizes be rejected and there is no significant effect of the auditors opinion on share prices and returns in Tehran Stock Exchange. Originally, that is, no information content of the audit opinion in decision making.