The global economic crisis expresses the tensions of the accumulation regime, impossible to solve by the ordinary functioning of the system. The crisis of 1929, known as the Great Depression, had been considered, until the beginning of this century, the strongest, followed by the crisis of the seventies, which marked a new stage of crisis by rising prices oil. Since then, the global economy has faced a succession crisis, with shorter recovery periods, until the outbreak of 2007. This article defines the concept of economic crisis itself, characterizing the prevailing economic system in the world, responsible for structural failures which are linked to all the common elements of an economic crisis. Finally we review three factors of the crisis 2007-2009, even affect the global economy.