This article provides lessons learned on the experience ofseveral countries that have succeeded in building a wellfunctioning government monitoring and evaluation (M&E)system. Discussions on this article are focused on: terms andconcepts in the field of M&E, outputs of M&E, utilization of M&Einformation, key success and pre-requisite to succes ininstitutionalizing M&E as well as actors M&E. The result indicatesthat ouputs of M&E system are used oftenly for: (i) supportingpolicy making, performance budgeting and national planning;(ii) helping ministries in their policy development and policyanalysis work, and in program development; (iii) managingactivities at the sector, program and project levels; and (iv)enhancing transparency and support accountabilityrelationships. The successful institutionalization of M&E involvesthe creation of a sustainable, wellfunctioning M&E system withina government, where good quality M&E information is usedintensively. This implies that key success for institutionalizingM&E system depends on: utilization of M&E information, qualityof M&E information and sustainability. Meanwhile prerequisiteto successful in institutionalizing of the M&E system must besupported by a substantive demand from the government,insentive mechanisms, powerful champion, and provision oftraining in a range of M&E tools, methods, approaches andconcepts. Actors involved in M&E system are not onlygovernment. Civil society (i.e., universities, NGOs, researchinstitutes, think tanks and the media) also can play a role inM&E in several ways, including as a user and producer ofM&E information.Keywords: monitoring, evaluation, policy, program, project