Measuring and evaluating the efficient use of resources of Bank branches plays a decisive role in a Bank’s strategic planning. Usually, efficiency is measured by using accounting ratios, such as labor productivity, capital productivity, return on assets etc. When these ratios are properly used, they provide significant information regarding the effective operation of the branch, and contribute in carrying out intrabank comparisons and comparisons over a period of time. However, by using such ratios, an important part of the branch operation remains uncovered: the measurement of the effective use of the resources. New mathematical programming models that are related with the degree at which each branch makes use of its resources, are applied to deal with the weaknesses of such ratios. This study discuss the limitations of using accounting ratio analysis for assessing performance and, presents and interprets the results from the application of mathematical programming models in a sample of branches of a Greek Bank.