In the national and international contexts there is evidence of increasing concentration of the banking sector. Such restructuring can be observed when comparing the number of financial institutions for 10 years with the number recorded in 2013. Accordingly, this article aims to evaluate the concentration of the banking sector in the period 1996-2013, as well as changes in exchange interest of its main products in the same period. We analyzed the sector concentration based on four Herfindahl-Hirschman indicators (HHI), the concentration ratio (CRK), the Hall-Tideman Index (HTI) and the Theil Entropy (ET) and later performed the correlation analysis between these indicators interest rates. The Herfindahl-Hirschman Index (HHI) showed that the sector is moving towards a moderate concentration, when considering the variables total assets and net worth. As for net income and total deposits, the sector shows moderately concentrated. The Concentration Ratio (CRk) showed that the four largest institutions in the country hold almost 50% of the total equity of National Financial System and over 55% of total assets, total net income and total deposits. Other indicators showed that the industry is unconcentrated, with, however, a clear increase in concentration towards these indicators. As for the evolution of interest rates, although the industry move toward a moderate concentration, there was decline in this indicator, in all forms studied.