This research has studied effect of compulsory rotation of auditing institutes on quality of financial reporting in the companies listed in Tehran Stock Exchange. Main goal of the research was to answer this question that if there was significant relationship between compulsory rotation of auditing institutes and quality of financial reporting. To study quality of financial reporting, variables of distinction between declared and diagnostic tax, accounting estimations, deviation from laws, accounting mistakes and accounting procedures have been used as dependent variables. Statistical population including two sample groups with 50 companies as test group and 50 companies as control group was studied for 4 years during 2009-2012. The required data of the research includes difference discovery acceptance ratio before and after compulsory rotation of auditing institutes. Results of our research showed that rotation of auditing institutes had significant relationship with declared and diagnostic tax distinction and accounting mistakes and increased differences discovery acceptance ratio. But such relationship was not found between rotation of auditing institutes and accounting estimates discovery, deviation from laws and accounting procedures.