Regarding the recent financial and banking crisis, corporate governance has gained a more important role on firms and financial institutes' success. Investigating the reasons for the failure of several firms and big banks, which has caused great losses for shareholders, shows that these losses are mostly due to weak corporate governance structures in these organizations. In order to answer the questions about the quality and quantity of the relationship between corporate governance and banking sector indices, we use panel data regression for a sample, including 15 selected banks from developing (D8) and developed (G7) countries during 2005 to 2014. In order to check the reliability of the estimated parameters, we used F-test and to choose between random or fixed effect models, we used Hausman test. The results confirm that corporate governance measures have a positive and significant impact on selected banks' profitability indices. It is also notable that the magnitude of estimators and their level of significance are different between developing (D8) and developed (G7) countries.