Although marine mammals, particularly cetaceans, have been protected in Korea for more than 24 years after a commercial whaling moratorium in 1986, relatively little effort has been focused on assessing their current status of marine mammals in this area after this protection and the efficacy of this protection. Thus, for the first time, the status of marine mammals in Korea was investigated using potential biological removal (PBR) and mortality data. A total of 5 stocks of marine mammals were investigated and 4 stocks experienced anthropogenic mortalities that exceeded their estimated PBR level. Therefore, these 4 stocks were considered strategic. These mortalities were mainly associated with commercial fishing activities. To conserve and manage marine mammals in this area effectively, it urgently needs to investigate the efficiency of various bycatch mitigation measures and to apply these measures in field actually for reducing bycatch. This study has advanced our understanding of the current status of marine mammals in Korea, but quantitative data on abundance are not available for most small cetaceans such as common dolphin, harbor porpoise. Thus, further study needs to examine abundance of small cetaceans for investigating of the current status of these stocks in Korea.