OBJECTIVE: The study aimed to estimate the annual societal costs of rotavirus infection in Korea for the year of 2005. METHODS: The incidence rate used was from the data reported at Jeoungeub District from July 1, 2002 through June 30, 2004 (11.6 cases/1000 children < 5 year old for inpatient and 45.3 cases/1000 children < 5 year old for outpatient). The number of patients with rotavirus was estimated using this rate and the number of 0-4 populations (1,165,686persons) in Korea. The medical costs for children with rotavirus (ICD code: A08.0) were extracted from the Health Insurance Review and Assessment Service database in Korea. The patient survey was conducted to get information about non medical costs and indirect costs.  RESULTS: The annual national cases for outpatients with rotavirus were estimated at 55,030 and for inpatients 14,092 cases, for children < 5 year old. No death due to rotavirus was reported in 2005. The total cost due to rotavirus infection was US$13.1 million including US$10.7 million for direct medical cost (82.1%), US$1.7 million for direct non medical cost which account for transportation and extra diapers, and US$0.66 million for missed work due to care. The average cost per case of rotavirus disease was US $189 (US $667 per inpatient case and US $67 per outpatient case). Conclusion: Rotavirus infection brings not only medical costs but also non medical and indirect costs and it would be significant burden in Korea. The impact of rotavirus to quality of lives and health of patients' caregivers were not considered in this study but should be included for the further research.