Although the Health Assessment Questionnaire (HAQ) and the Modified Health Assessment Questionnaire are useful tools for assessing and monitoring patients with rheumatic diseases, they have a "floor effect" and do not fully reflect the psychological status of patients. Recently, the Multidimensional Health Assessment Questionnaire (MDHAQ) was developed to overcome these shortcomings. We translated the MDHAQ into the Korean language and evaluated its reliability and validity for use with Korean-speaking patients with rheumatoid arthritis (RA). The questionnaire was translated into the Korean language by three translators, who were aware of its objectives, and it was translated back into the English language by three different translators. One question was modified to reflect Korean culture, and imperial measures were changed to metric measures because most Koreans use the metric system. The Korean MDHAQ was administered to 136 patients with RA who were attending the outpatient rheumatology clinic at the Chonnam National University Hospital (Gwangju, South Korea). Test-retest reliability was assessed in 101 patients after 1 week. To assess criterion validity, we compared MDHAQ scores with HAQ scores and the American College of Rheumatology (ACR) functional class. To test construct validity, the MDHAQ was compared to ACR core criteria (tender and swollen joint count, pain, patient's global assessment, physician's global assessment, erythrocyte sedimentation rate, and C-reactive protein), the Beck Depression Inventory (BDI), and the State-Trait Anxiety Inventory (STAI). The test-retest reliability was analyzed by computing kappa statistics, which ranged from 0.60 to 0.76. Cronbach's alpha coefficient ranged from 0.892 to 0.938. The MDHAQ was significantly correlated with the HAQ and ACR functional class (all p<0.001). The correlations between the MDHAQ scores and the ACR core set, BDI, and STAI were all high and statistically significant. The Korean version of the MDHAQ is a reliable, valid tool for assessing Korean patients with RA.