The National Immunization Program (NIP) is the most cost-benefit effective policy of countermeasures against vaccine preventable diseases (VPD). The national level of vaccination coverage is the critical process indicator of NIP performances. In the Republic of Korea, the government has expanded the vaccination coverage by over 95% through reduction of vaccination barriers such as budgetary burden (out of pocket money) and physical accessibility. The Korea Centers for Disease Control and Prevention (CDC) publicly reported the national level of vaccination coverage for the first time in 2016. The vaccination coverage of children aged 12, 24 and 36 months in 2015 was 94.3%, 92.1% and 88.3%, respectively. This report will briefly describe methods of standardizing and collecting data, results of vaccination coverage rate, and suggestions on future directions for maximizing data utilizations from the National Registration Information System.