This paper suggests the core competency index of PCO employees. To effectively achieve its objective, this study establishes the definition and characteristics of "core competency," as well as stating the need for introducing the core competency index for PCO employees based on literature review on the definition and characteristics of PCOs and stakeholders. Due to the lack of earlier researches on PCO employees, this paper includes in-depth interviews conducted on 15 PCO employees, resulting in an index of 53 core competency factors. In the empirical analysis, core competency factors of PCOs have been also confirmed by exploratory factor analyses which have drawn the same five dimensions from 16 items. The core competency scale for PCOs is based on the following five underlying factors: communication, flexibility, ability of business progress, ability of foreign language, and planning and management. This paper draws the conclusion that PCOs must create long-term interests through clients and also make endeavors in increasing the satisfaction of clients by differentiating, managing and reflecting core competencies of PCO employees, as they are required by the clients as corporate survival strategies.