The general belief in the business organizations is that investment on Information Technology will add value to the firm But every business decision has to be made by considering its impact on the goal of the firm in this regard the investment on information technology has to be seen in terms of its likely contribution to the goal of the firm.This book aimed at finding out the effect of core banking Information technology system on performance of commercial bank of Ethiopia as a case study. It used customers' satisfaction and employees' performance/efficiency as independent variables to measure performance of the bank.