This paper examines and evaluates the ecclesiology of Korean mega-churches. It focuses on Myung-Sung Church, the world’s biggest presbyterian church. Its founding pastor, Sam-Whan Kim is a presbyterian minister, who traces his ecclesiastical heritage back to John Calvin, but his ecclesiology resembles a form of the medieval church that Calvin criticized. This paper examines Kim’s understanding of the church focusing on its relationship to Christ; also, this paper examines Kim’s understanding of a minister’s authority. Then, this paper evaluates his ecclesiology against Calvin and the medieval church. Lastly, this paper introduces the doctrine of ascension, which would expect to put Korean mega-churches back into their Reformed Heritage.