Which kind of connection exists between the Rio Conference in 1992 and Rio + 20? Our article outlines the stages of a process that has been going on for twenty years, considering its strengths and weaknesses and contextualizing it according to the different economic and political scenarios that have characterized these years. Our analysis starts from the defi nition of «sustainable development» and the fall of the Soviet bloc in the early 90s. It continues with the Kyoto Protocol and its ratifi cation, considering the new global equilibrium determined by the new emerging countries like China and India. Finally, it ends by presenting the Rio + 20 themes: Green Economy and Poverty reduction, considering the effects of the global economic crisis of the last years.