Internal audit has been used in enterprises and public institutions management for a long time. Application of internal audit may be implemented by external regulations(e.g. recent changes in the New York Stock Exchange rules or Sarbanes-Oxley Act of 2002 in U.S.) or by entity itself on the purpose to improve its operations. Depending on the industry organization is acting, nature and complexion of organization and other factors, internal audit function maybe used toward various directions. In financial institutions(banks, insurance companies, etc.) the need for the internal audit activity is expressed over objective to assure cashflows, liquidity of the institution and safeguarding of the assets. This article covers the survey of internal audit interpretations, internal audit functions and the role of internal audit in enterprise risk management. Many international leading companies have recognized value of the enterprise risk management model that allows managing enterprise risks as a respond to rapid environmental changes.