The role of an internal audit is of indisputable importance for every business. The emergence of many risks and the uncovering of financial scandals in recent years has led to increase of adoption of a risk-based internal audit (RBIA) by firms. This paper investigates the critical variables for the implementation of RBIA in Greek companies and examines the relationship between the above variables and RBIA implementation using data collected by 105 internal auditors, external auditors, directors and managers of Greek companies. The results of the regression analysis reveal that the quality of internal audit, the review concern, the risk management system and compliance with the international standards for the professional practice of internal auditing are positively related with statistical significance to the implementation of RBIA. Consequently, management should focus on these issues in order to apply RBIA. Our research also provides valuable insights into the impact of the economic crisis on firms and the country’s wider economic environment.