In this chapter the spotlight will be on descentralised development cooperation. The main of this document is to enhance our understanding of the dynamics and the potencial impact of this type of cooperation on municipal governance and sustainable local development. First, is adressed the changing role or local goverments in the South. In the next section, the historical background of municipal international cooperation is presented, followed by an account of the increasing number of international municipal partnerships (twinnings) over the past few decades. Then the chapter focuses on some contextual factors that seem to inspire these new forms of decentralised development cooperation through city linkages. Subsequently, an overview of the wide rage of C2C support programs will demostrate the diversity and ambiguity of the concept, but also show the gradually increasing level of professionalism and institutionalisation of C2C practice. Finally, based on a number of case studies drawn from literature, an attempt is made to define general success factors and challenges to city twinning.