During the twentieth century, democracy became a central concept when grounding and legitimizing political action. The Chilean Marxist Left was not alien to this phenomenon. Based on periodical, doctrinal journals, memoirs and public discourses, in this article we study the political and conceptual trajectories of democracy in the doctrinal and strategic elaboration of the main left-wing parties and movements between the 1950s and the 1980s. In that period, democracy and revolution became conceptually decoupled. While the conflictive construction and application of a transition project to socialism incorporated the democratic ideal, the 1973 defeat forced a general restructuring, marked by the choice to reconstruct a representative democracy rather than aspire to revolutionize social structuress.