OBJECTIVES:  The aim of this study was to estimate the annual societal disease burden of irritable bowel syndrome (IBS) in Korea for the year of 2008. METHODS: The claim data with IBS were extracted from the Health Insurance Review & Assessment Service database in 2008 of Korea. After definition of patient with specialists, the prevalence and medical costs were calculated. The number of outpatient visits and length of hospital stay also were calculated to estimate transportation cost and productivity loss. RESULTS: The annual national patients with IBS were estimated to 1.30 million with 753,688 (57.79%) for female. The results showed that the crude prevalence of IBS was 2.68% (95%CI: 2.66%-2.71%, 2.25% for male and 3.12% for female) in 2008. The total cost due to IBS was 14.9 billion won (1$=1047.30 won, 2008) including 348 million won for direct medical cost (2.33%), 88 million won for nonmedical cost (transportation costs), and 14.5 billion won for lost work due to illness. CONCLUSIONS: The disease burden of IBS appears to be high because of the high morbidity although not a significant cause of death. The result is likely to underestimate due to using claim data and strict definition of patient. However, this data might be useful and necessary to support evidence based decision making for IBS.