This article provides lessons learned on the experience of several countries that have succeeded in building a well functioning government monitoring and evaluation (M&E) system. Discussions on this article are focused on: terms and concepts in the field of M&E, outputs of M&E, utilization of M&E information, key success and pre-requisite to succes in institutionalizing M&E as well as actors M&E. The result indicates that ouputs of M&E system are used oftenly for: (i) supporting policy making, performance budgeting and national planning; (ii) helping ministries in their policy development and policy analysis work, and in program development; (iii) managing activities at the sector, program and project levels; and (iv) enhancing transparency and support accountability relationships. The successful institutionalization of M&E involves the creation of a sustainable, wellfunctioning M&E system within a government, where good quality M&E information is used intensively. This implies that key success for institutionalizing M&E system depends on: utilization of M&E information, quality of M&E information and sustainability. Meanwhile prerequisite to successful in institutionalizing of the M&E system must be supported by a substantive demand from the government, insentive mechanisms, powerful champion, and provision of training in a range of M&E tools, methods, approaches and concepts. Actors involved in M&E system are not only government. Civil society (i.e., universities, NGOs, research institutes, think tanks and the media) also can play a role in M&E in several ways, including as a user and producer of M&E information.