According to the institute of internal auditors practical guide internal auditors evaluate risksrnfaced by their organizations based on audit plans with appropriate testing. Internal auditorsrnneed to be alert to the signs and possibilities of fraud within an organization. The role of internalrnaudit must be determined in the investigation process in the internal audit regulations as well asrnin the fraud related policies and procedures.rnThe general objective of the study is to examine the role of internal audit on fraud detection andrnprevention in Ethiopian Ministry of Revenue.rnThis study was conducted by using a cross sectional survey to investigate the role of internalrnaudit and to compute this study four branch of Ethiopian Ministry of Revenue were selectedrnpurposively selected. Descriptive statistic was used to analyse the data from the survey by usingrnSPSS version 20. Both primary and secondary data were used as a data source.rnThe study found out that there is in appropriate organization set up and undefined scope ofrninternal auditors in the organization and in related to fraud detection, inadequate competence ofrnauditorsâ€™ and independence problem toward the usefulness of internal audit work to detect andrnprevent fraud. It also assess the internal audit risk assessment that contributes in detection andrnprevention of Fraud.rnThe study concluded that internal audit staff of Ethiopian Ministry of Revenue lacks thernnecessary competence and independence to prevent and detect fraud. Fraud risk assessment isrnnot exercised which support internal audit to control fraud. As a result, internal audit have hadrnlimited role in fraud prevention and detection in the study organization.