The objective of the Maintenance Rule (MR) is to require monitoring of the overall continuing effectiveness of licensee maintenance programs to ensure that the safety related and certain nonsafety-related SSCs are capable of performing their intended functions. In Korea, as risk informed applications and regulation become active, the necessity of Performance Based Regulation (PBR) has increased. The objective of this article is to study the effectiveness of MR based on performance and feasibility of MR adoption at Korean Nuclear Power Plants (NPPs) for effective maintenance and regulation.