The cost of illness, a monetary estimate of costs arising from illness, serves as a useful indicator for assessing the socioeconomic value of health and for analyzing disparities in health outcomes between groups and across subnational regions. The cost of illness has been growing in Korea, with the proportion due to premature death from illness declining and the proportion due to living with illness growing. From a sociodemographic perspective, there is a need for health management policies targeting the population groups with increasing health care utilization, not least those age groups of either sex that remain a major active part of Korea’s socioeconomic landscape. Regional variations in the cost of illness have increased in recent years across cities, counties, and districts throughout the country. Policy interventions are required to address disparities in transportation expenditures, which this study finds vary more pronouncedly across regions than the other cost items. Moreover, caregiver costs also demand attention, as their regional variation has shown an increase in recent years.