OBJECTIVES: To estimate the annual prevalence, the related medical costs, and health care resource utilization of patients diagnosed as herpes zoster (HZ) and post-herpetic neuralgia (PHN), respectively, with different immune status in South Korea. METHODS: This study is a retrospective analysis using the Korean National Patients Sample 2009 database of the Health Insurance Review and Assessment Service (HIRA K-NPS). Results of the sample database were extrapolated to the total Korean population aged ≥ 40 years. HZ and PHN patients were identified from diagnostic codes, and categorized into three subgroups based on the severity of immune status; non-compromised, mild to moderate and severe status. Medical costs included all HZ- or PHN-related costs incurred at medical facilities and medication costs. RESULTS: The prevalence of HZ (or PHN) was 15.53 (or 2.13) per 1000 persons among those aged ≥ 40 years in South Korea. The annual medical costs per patient for HZ (or PHN) management were US$191 (or $177). The average number of outpatient visits, emergency department visits and hospital admissions of HZ (or PHN) patients were 3.75, 0.01, and 0.05 (4.44, 0.01, and 0.03) per annum, respectively. With regard to the severity of immunodeficiency, patients with severe conditions were related to higher prevalence rate, medical costs and health care utilization. CONCLUSIONS: HZ and PHN cause considerable disease burden in South Korea, especially among immunocompromised population. Considering rapidly aging population and increasing prevalence of immunosuppressive conditions, the disease burden is likely to increase. The findings of the present study can serve as important baseline data for policy decision making to reduce the burden, such as the development of a HZ vaccination recommendation.