Once perceived as taboo for many donors, assistance toward the police force of fragile and transitional countries was (re)introduced as a major component of development assistance for the international community in the post-Cold War era under the label of "police reform" and "security sector reform (SSR)." What makes this (re)introduction of police force assistance in the post-Cold War era important and distinguishes it from that of the Cold War? How can police reform be understood in the context of peacebuilding? These are the questions addressed in this paper. The first section will explain what changed in the 1990s that prepared the ground for (re)introduction of the assistance to the security sector, including the police force, as part of the development agenda. Put differently, how did this change come to take place in the post-Cold War period? The second section will illustrate how that development impacted upon the consideration of police reform: that is, how police reform is understood within the context of peacebuilding. The paper will conclude with some future agendas to be addressed in police reform literatures. In short, this is a research paper that seeks to critically examine how assistance to the police forces of fragile and transitional countries is understood and discussed in the context of peacebuilding.