This paper is aimed to analyse the functions of the European Court of Auditors and of a domestic Court of Auditors, the Italian one, to underline how performance auditing is important in fighting corruption and mismanagement in the public administration. Indeed, performance auditing is an important instrument in order to improve transparency, efficiency and accountability in public administration. This is an important issue when domestic public administrations are managing EU funds. Performance auditing is a cornerstone to ensure good public sector governance. The establishment of institutions aimed at providing accountability is an important step in order to guarantee transparency and, consequently, democracy but, more important, is to ensure their efficiency. An efficient public administration is necessary in order to guarantee prosperity in a country.