Many companies have recently been choosing information technology (IT) out-sourcing in response to complicated information systems and various internal requirements. In order to monitor and maintain a high quality of IT outsourcing vendors’ services, it is necessary to develop a system to evaluate IT outsourcing customer satisfaction. The system can be used as a tool for choosing IT outsourcing providers. Through the literature reviews and experts’ interviews, we propose the evaluation system of IT outsourcing customer satisfaction. Using AHP (analytic hierarchy process) technique, attributes associated with customer satisfaction in IT outsourcing environments are then rated in terms of their importance. The customer satisfaction evaluation system is applied to IT outsourcing service receivers in Korea to demonstrate its practical implications.