This research is a case study aimed at analyzing the role of internal audit in preventing corruption in public sector. The study was conducted by observing the condition and data analysis. The analysis is done by comparing the efforts made with the occurrences and / or audit findings that occurred. The results show that internal audit has made prevention and detection efforts related to fraud events, but there are weaknesses in internal controls that still have not been able to prevent fraud events. As one of the objectives of supervision from the inspectorate general of the Ministry of Health of the Republic of Indonesia is to improve the effectiveness, internal control and risk management of all execution of functions and duties within the Ministry of Health, therefore it is necessary to design additional controls that strengthen existing controls. A fraud control system is a control developed and designed to prevent, deter and disclose fraud events. The system results from strengthening or deepening of existing governance systems and is influenced by the conditions of each organization.