The study of the evolution of the work force in the Québec census metropolitan area, between 1971 and 1981, shows that the phenomenon of polarization of occupational structures extends into several zones in the region. Based on statistical, graphical and cartographical analysis, the research draws parallels between the changes produced in the professional structures and the economic activity (male and female) in different work areas. On this spatial basis, the polarization is especially located in the outlying suburban areas. It is linked partially to the tertiarization of economies and partially to the internal restructuring of the work force, observed in several sectors of economic activity. The evolution of the work force is also characterized by an upgrading of the qualifications. This second tendancy is mainly located in the central work areas.