The purpose of this research is to investigate the role of auditors' characteristics, including knowledge requirements, skill requirements, and ethics requirements in fraud prevention. This research is applied in terms of purpose and descriptive in terms of data collection method, and the information needed to check the hypotheses was collected by means of a questionnaire. The statistical population of the study consisted of two groups of auditors, including independent auditors (auditors working in audit institutions that are members of the Iranian Certified Public Accountants Association and the Audit Organization) and auditors of regulatory bodies (including auditors working in the State Inspection Organization, Audit Court, and Ministry of Economy and Finance) Questionnaires were distributed among them and finally 384 questionnaires were collected and their reliability and validity were checked and they were confirmed. The hypotheses of this research have been analyzed by structural equation modeling method. The findings of the research showed that from the point of view of external auditors as well as from the point of view of auditors of regulatory agencies, skill and ethical requirements in auditors are effective in preventing fraud, but knowledge requirements in auditors do not have a significant effect in preventing fraud. The results of this research are consistent with the theories of competence and planned behavior. Considering that auditors play an important role in the level of trust of users of financial statements, it is necessary to pay attention to their characteristics in preventing fraud in both the private and public sectors.