Abstract. The purpose of this work is to evaluate the efficiency of the biggest commercial
banks that operated in Greece at the financial year 2009. The method used is Data Envelopment
Analysis. Each bank is modelled as a linear system with multiple inputs and outputs. The
data used was derived from the balance sheets, income statements and the annual report of
each commercial bank. These data include the interest expenses, fixed assets, deposits etc.
To estimate the relative efficiency of the chosen DMU’s the MS Excel add-in program
xIDEA 2.1 is employed. The results indicate several inefficiencies that have no direct relation
to the profitability of such institutions.