The aim of the present research is to study the effect of ethical behavior of the board of the directors on audit performance quality. The studies indicate that the ethical behavior of the board of the directors will have a positive effect on improving the audit performance quality. Two measures of audit quality are to select a big audit firm and market share of auditor. The present research is an applied research and from aim point of view; is a descriptive study. The statistical population of the present research includes all the firms listed on Tehran Stock Exchange in the time period of 2010 - 2012 and the sample size has been determined with the use of filtering method which is obtained to be equal to 105 firms after the elimination of irrelevant observations.
The findings obtained from data analysis at 95% confidence level indicate that there is a direct and significant relationship between ethical values of the board of the directors and the selection of the Audit Organization as the audit firm in Tehran Stock Exchange. However, the results indicate no significant relationship between ethical values of the board of the directors and the market share of the auditor.
