In recent years, significant changes in the forms of Government have occurred in Colombia, as a consequence of many different institution-related factors, inter alia the availability of new tools for civil society's participation, decentralization and political parties' reform. These factors have redefined activities and relationships of local Government's actors, among themselves, the councilpersons. From the governance standpoint, this paper aims to lead to a better understanding of councilpersons and their relationships with other stakeholders that are also people's representatives: public and private organizations. Availability of empirical data on this subject is very limited in this country, and the city of Medellin is a case in point. Based on the identified trends (cooperation, mediation, competition and lack of relationship), the article highlights the prevalence of cooperative relations and concludes that the principles of positive governance (plurality, interdependence and cooperation in management), are tempered by several factors, including political and institutional changes and the characteristics, motivations and strategies of the actors involved.