During the past three decades, Korea has strived to catch up with the advanced nuclear countries and filled up wide blank areas in nuclear technology with consistent national nuclear development programs. The regulation has been playing a major role in making today’s achievement in the nuclear arena by setting up appropriate codes and standards and also by introducing updated regulatory requirements. Especially, over the past decade, there has been a lot of improvement in nuclear safety through regulatory initiatives in response to safety issues coming from domestic or foreign nuclear incidents. Safety inspection activities came to cover both the primary and the secondary sides to get more coherent regulation and to reduce the unscheduled shutdown resulted from secondary side. The risk insight was also more and more brought up into regulation, such as in risk-based inspection. As many of nuclear power plants are getting older, PSR as a comprehensive evaluation system, has been introduced and a complete set of rules for continued operation has been in effect from 2005. This paper will present how the Korean regulation addresses these challenges.