In recent years, medium and large enterprises in Serbia have been introducing the mechanisms of internal auditing and control, primarily upon request of capital owners and investors. Privatization and transformation of enterprises have accelerated the process of accepting control mechanisms in companies. New owners increasingly demand reliable and independent assessments of financial statements of companies which they manage. In conditions characterized by high uniformity of heterogeneous financial statements, company management searches for a better way of establishing control in company, which is a long and continuous process. These processes cannot be considered separately from the ethical and responsible approach of people authorized to conduct internal control processes in companies. Fully independent internal audit in medium and large enterprises in Serbia brings a new quality in the detection of negative aspects and characteristics of companies. It is important to mention that even in the most developed countries with a long tradition of internal auditing and control, there is no single established internal auditing mechanism which can provide expected results and absolute protection from unwanted effects.