I am a director of Department of Transplantation Surgery, Severance Hospital in Seoul, Korea. Initially my specialty was kidney transplantation (clinical). But since 2005, I also involved in liver transplantation as a surgeon of recipient operation team in living donor liver transplantation. Currently deceased donor kidney transplantation and liver transplantation are my specialty in our transplant center. My clinical research is based on huge database of kidney/Liver transplantation in Severance Hospital which was accumulated since 1990s (accumulative cases of 5,000 kidney transplantation and 1,500 liver transplantation). I am also a professor of Department of Surgery, Yonsei University College of Medicine after year 2008. And I am the director of The Research Institute for Transplantation in Yonsei University. I have interest in research related with transplantation. The action mode/effect of immunosuppression on chronic rejection and peri-transplant immunologic monitoring, such as sCD30, PRA and Donor-specific antibody, is main focus of my research laboratory. I am an executive director (Publication) of Korean Society for Transplantation (KST) and key member of Administrative Committee for Organ Transplantation in Korean Network for Organ Sharing (KONOS). Now I work as an executive director of Korean Organ Transplantation Registry (KOTRY).