This paper analyzes the effects and implications of the 2003 political reform and its impact over the Partido Liberal Colombiano (PLC), exploring how the institutional changes configured a frame for the reorganization of the liberal collectivity until 2010. The first part of the paper exposes the development of the party system in Colombia and the incentive base structure in the institutional framework before and after the reform. To account for changes in the PLC, a review is made for the main debates given within the liberal party in Congress regarding the reform and subsequent modifications. Finally, this paper shows the impact of the reform over the behavior of the PLC as an organized party and its individual members, supported under the concepts of the neo-institutional theory.