The need for evidence-based decision making in immunization programs has increased due to the presence of multiple health priorities, limited human resources, expensive vaccines, and limited funds. Countries should establish a group of national experts to advise their Ministries of Health. So far, many nations have formed their own National Immunization Technical Advisory Groups (NITAGs). In the Republic of Korea, the Korea Expert Committee on Immunization Practices (KECIP), established by law in the early 1990s, has made many important technical recommendations to contribute to the decline in vaccine preventable diseases and currently functions as a NITAG. It includes 13 core members and 2 non-core members, including a chairperson. Core members usually come from affiliated organizations in internal medicine, pediatrics, obstetrics, microbiology, preventive medicine, nursing and a representative from a consumer group, all of whom serve two year terms. Non-core members comprise two government officials belonging to the Korea Centers for Disease Control and Prevention (KCDC) and the Korea Food and Drug Administration. Meetings are held as needed, but at least twice a year, and sub-committees are formed as a resource for gathering, analyzing, and preparing information for the KECIP meetings. Once the sub-committees or the KCDC review the available data, the KECIP members discuss each issue in depth and develop recommendations, usually by a consensus in the meeting. The KECIP publishes national guidelines and immunization schedules that are updated regularly. KECIP's role is essentially consultative and the implementation of their recommendations may depend on the budget or current laws.