The sovereign debt crisis and the new legal framework of European economic governance have forced most of the EU Countries to adopt stricter fiscal rules. In order to support budget decisions and fiscal policy choices on a strictly technical level, Independent Fiscal Institutions have often been set up in Europe. The present study aims to develop a comparative analysis of Independent Fiscal Institutions in order to better understand the role given to these public bodies in different countries. The effectiveness of so-called “fiscal watchdogs” depends on their independence and the reputation they are able to build. They are or become strong if their creation follows the path of the country’s constitutional traditions and there is compatibility with the specific political context. Taking into particular consideration some experiences (mostly European), the paper discusses the connections between introducing an Independent Fiscal Institution and reinforcing the activities of public policy evaluation, especially in Parliaments. The development of a culture of evaluation could in fact better ensure the accountability of Government, allowing legislative Assemblies to perform a more efficient oversight on all public policies, among which the most important is considered the fiscal one.