The objective of this paper was to analyze the evolution of the Structure of the Brazilian market of popular cars in the period from 1990 to 2005. Information on the number of units sold by each firm in the domestic market have been used to determine each firm’s market-share, levels of concentration and the Herfindahl- Hirschman Index. The results have pointed that, although reduction in the concentration of this market during the period have occurred, the market is still strongly concentrated according to the levels established by the Office of Economic Investigation (SEAE) and by the Office of Economic Defense (SDE) for the exercise of the coordinated market power.