The Author aims to show the results presented by the Clean development Mechanism (CDM) created under the Kyoto Protocol as tool to promote a flexible scheme to meet the commitments. After thirteen years of CDM operation, results exposed a discouraging panorama as GHG emissions keep increasing. The situation got complex as it has been some barriers that prevented CDM optimal operation. With a new second commitment period entering into force, CDM scheme provides an uncertain outlook so far. The first period results are shown along with the characteristics of the second one and the future CDM market trends. It is also reviewed the CDM background, following by the analysis of the periods’ situation and possible actions that can be taken in order to enhance CDM as emissions reduction strategy, finished by conclusions from the author.