Clinical Ethics Support Services (CESS) aim to assist those confronting ethical issues that arise in the course patient treatment. CESS enhances the quality of health care by identifying and resolving ethical issues in a systematic fashion. In Korea, while the function of Institutional Ethics Committees varies somewhat from one institution to the next, most committees focus mainly on administrative services related to life-sustaining treatment. Due to improvements in medical technology and a rapidly changing social environment, a multidisciplinary approach is essential to assisting medical personnel in the area of clinical ethics. This study examines the key participants and core competencies of CESS providers and considers what knowledge or skills could improve them. It is argued that the core competencies for CESS are the ability to investigate and evaluate ethical issues and the ability to reach agreements by means of arbitration and conciliation in the case of disputes. Understanding the suffering of individual patients and recognizing the uniqueness of each patient are also essential to effective mediation on critical life-related issues. CESS providers should be trained to understand the difficulties that patients facing existential problems experience and to advocate for those patients.