**Abstract**

The purpose of this chapter is to demonstrate the importance of tax risk management in mergers and acquisitions processes by conducting an investigative work called due diligence. To achieve this objective, bibliographic and documentary research was used, as part of exploratory research. In topic 1 it is evidenced that the complexity of tax systems around the world has demanded increasing attention from companies to avoid undesirable cash disbursements for payment of infringement notices arising from questioning by tax authorities related to improper procedures of companies when paying taxes. Additionally, it has required them to be diligent in identifying lawful tax planning alternatives to optimize the tax burden on their operations. In topic 2 the responsibility of company administrators in the management of tax risks is exposed. Topic 3 explains the importance of accounting, tax and legal due diligence in merger and acquisition processes. Finally, topic 4 analyzes the main aspects of due diligence in the tax area. In view of all the exposed in this chapter, it will remain clear to readers the importance of the tax due diligence of the target company, as a way to minimize risks in the decision-making process of the managers of the purchasing company that may compromise the success of the merger and acquisition operation, as well as not subjecting them to administrative and judicial suits, for non-compliance with their fiduciary duties of diligence and loyalty in relation to the company of which they are executives. Additionally, the study's results suggest that companies—in compliance with the guidelines and limits set by the board—choose the appropriate and specific techniques of risk management, especially those related to minimization, immunization, and transferring these risks. The recommendations derive from the need to identify and manage tax risks, from the point of view of good corporate governance practices. This study may serve as a reference to companies in general, when studying, developing, and implementing recommendations for the identification and minimization of tax risks, as well as in the development of a work program that allows them to conduct due diligence work in target companies.

**Keywords:** tax system, tax risks, tax due diligence, managers responsibilities, merger and acquisition
