The ports of Buenos Aires and Montevideo operate in the same market, which stretches along the River Plate Basin. The congruent core hinterland includes the metropolitan areas of Buenos Aires and Montevideo. The extended hinterland embraces Paraguay, Bolivia and several interior regions of Argentina. This chapter analyses the performance of the two ports at two points in time - 1999/2000 and 2003/2004. In 2001/2002, Argentina and Uruguay suffered from a deep economic crisis and developed various strategies and environments for port governance in order to deal with these changing conditions. The Matching Framework is applied to understand the different outcomes of the port devolution processes in each country.