Objective: This study aimed to analyze the operations of Armed Forces Capital Hospital (AFCH) Institutional Review Board (IRB) from 2017 to 2021 and to review the application of its protection program for military research subjects, so that we could suggest future directions in operating military IRB. Method: Documents from the AFCH IRB records over 5 years were analyzed. These covered operational metrics and activities in IRB: review protocols, IRB meetings, researchers, the composition of IRB, Standard Operating Procedures (SOP) and review management system. Results: The annual average number of IRB members was 16.2 and all IRB members have been composed of civilians since 2018. Scientific and non-scientific (NS) members were 11.4 and 4.8, respectively. Affiliated members and non-affiliated (NA) members were 10.2 and 6 persons per year, respectively. The IRB SOP included the protection program for military research subjects. The annual average number of review protocols was 28.2. Among the protocols, retrospective studies using medical records were most common (72%). Convened IRB reviews were held 4.4 times per year while expedited IRB reviews were held 42.8 times per year. Most researchers submitted one or two review protocols (77%). The internet-based electronic IRB system has been used since 2021. Conclusion: The number of NA and NS members in IRB was sufficient. The IRB chairman was elected from non-military affiliated member. The training to researchers about the protection program for military subjects would be necessary. The IRB SOP needs regular update regarding the protection program for military research subjects.