Internal audit as an independent function in the company evaluates internal control system, risk managament process and the process of corporate governance and provides an objective an independent opinion on their efficiency, effectiveness and application. The internal audit process consists of four phases: planning, critical examination and evaluation of the business, communicating results and monitoring progress. The main subject of this paper is to research and display the first phase of internal audit process. The goal is to determine the significance of the role of planning in the entire internal audit process. The planning approach enables the focusing of audit activities on important areas, more precisely areas of high risk. The final purpose of the planning is to reduce the probability of unexpected events so significant risks can reduce itself to a minimum level. Planning approach increases the likelihood of achieving the efficiency and the effectiveness of the internal audit department and ensuring value added for the company. By developing long-term, short-term (annual) and functional plans, Chief Audit Executive (CAE) affects on the overall peformance of internal auditing. Their interconnection and flexibility represent important characteristics in their effectiveness. In audit planning process it is necessary to efficiently allocate limited audit resources among each auditable unit. CAE develops the audit staff allocation, the budget and the timing of the audits with the possibility of applying planning techniques such as Gantt charts and network planning techniques.