OBJECTIVE: To estimate the prevalence and risk factors of fibromyalgia syndrome (FMS) and chronic widespread pain (CWP) in Korean. METHODS: Those who participated chronic pain field study in Uljin and Pohang, Kyongsangbuk-do in 2004 were evaluated for the prevalence of FMS and CWP. Diagnosis of FMS and CWP were made using American College of Rheumatology criteria. All 1,028 were interviewed based on a detailed questionnaire and 144 CWP patients were examined for tender points. RESULTS: Among the 1,028 participants (mean age+/-SD, 63.3+/-12.7 years), 676 participants were female (mean age+/-SD, 62.1+/-13.5 years) and 352 participants were male (mean age+/-SD, 65.7+/-10.5 years). There were 23 cases of FMS (2.2%), which consisted of 21 female cases and 2 cases of male. Prevalence of FMS was significantly higher in female compared to male (3.1% vs 0.6%, p<0.01). Prevalence of FMS showed increasing trend in the ascending order of age in decade (p<0.001). CWP was detected in 144 cases (14.0%), which consisted of 130 female cases and 14 cases of male. Prevalence of CWP was also significantly higher in female compared to male (19.2% vs 4.0%, p<0.001). Prevalence of CWP also showed increasing trend in the ascending order of age in decade (p<0.001). Except for age and sex, hating vegetables is an associated factor for the development of FMS in CWP [OR 18.7 (95% CI 2.4, 145.3)] and diabetes is a risk factor for the development of FMS in normal population [OR 3.7 (95% CI 1.1, 11.9)] on multivariate analyses. CONCLUSION: The prevalence of FMS and CWP were 2.2% and 14.0% in Korean, respectively. The prevalence of FMS and CWP were significantly higher in female and aged individuals. Aging, female sex, hating vegetables and diabetes are prognostic factors for the development of FMS.