Internal audit is an independent activity of the organizational unit that help the company and the management of the company to control and maximize the objectives. In order for the internal audit to be conducted regularly it is mandatory to follow to rules of the International Standards for the Professional Practice of Internal Auditing, Law on Audit and work in accordance with a code of ethics. Respecting the regulatory frame is necessary for authorized auditor. The organizational structure of the international auditing is a dynamic category that changes with growth and development of the company and it is changing on its own, complements and updates. The process of internal auditing includes a sequence of complex activities that are connected, mutually conditioned and their final result is the auditor’s opinion as the support to the management. Quality making of an audit from the beginning to the end of the process can significantly help a company in development, growth and achieving their goals, but if the process of internal auditing had been done unprofessionally the company won't revile their liabilities, unsuccessful and inefficient work. In Croatia a banka is defined by the law on banks as a financial institution that got a licence to operate from the Croatian National Bank and was established as a joint stock company with the headquarters registered in Croatia. Banking business is based on the principles of liquidity and solvency. Basic function of the internal auditing in the banks is to help the management to achive goals and to improve the efficency of risk management. Because of the dynamics of the banking system followed by modern technology it is necessary to constantly improve internal auditors. Analysing the research conducted by the PWC the trends are explored along with the qualitative and quantitative aspect of the internal auditing in the Republic of Croatia.