Though the advantage of RFID (Radio-Frequency Identification) technology has been consistently recognized over the years, there are still doubts about its actual effects on the BP (business process) improvement. In order to facilitate the adoption of RFID technology, it is required to measure RFID's positive effects on the BP. Our research focuses on the evaluation of BP efficiency at the Mail Distribution Center (MDC) in Korea. Via a simulation study that compares two BPs with and without RFID technology applied, we could induce key performance indicators of BP in MDC, which are important to evaluate the degree of improvement by applying RFID technology.