This article presents an approach to the institutions and regulations derived from the UNFCCC and the Kyoto Protocol. It is analyzed the performance of emission reductions markets during its three years of operations, mainly the instability of prices in European markets and their relationships with CER's, which are issued because of the projects from de Clean Development Mechanism (CDM) from developing countries. The article also establishes the achievements and limitations of CDM as well as the perspectives of these markets and its opportunities.