The purpose of this study is to propose guidelines for Introducing the JIT(Just-In-Time) purchasing to enhance the competitiveness of Korean manufacturing companies. This study employed an extensive survey on the use of the JIT purchasing systems among different Korean manufacturing companies to understand the current status of the JIT purchasing in use and to identify the benefits from implementing JIT purchasing. The survey has covered 163 manufacturing companies of different sizes from various sectors of Korean industries including electronics, automobiles, machineries, and textiles. The research results support that the JIT purchasing would contribute to increase the purchasing performances of Korean manufacturing companies.