Presented article is focused on evaluation efficiency of the building and loan associations sector between years 1999–2005 and on identification of the fundamental factors which influence the efficiency of the sector. From the efficiency indicators, ROAA, rate margin, commission margin, cost margin and risk margin were used. These indicators were rated from the building and loan associations accounting data. The criterion for the valuation of the building and loan associations sector were average values of the efficiency indicators achieved in the CZ bank sector as unit in given period. For evaluation of influence individual partial margin significance on ROAA correlation analysis was used.