OBJECTIVES: A standardized questionnaire is not available for use as a screening tool to assess individuals with MCS/IEI in Korea. The QEESI(c), originally developed by Miller & Prihoda in 1998, helps researchers, doctors, and their patients identify individuals with MCS/IEI. Therefore, this study was conducted in order to create a Korean version of the QEESI(c) and evaluate whether this Korean version could be used as an effective MCS/IEI screening tool in Korea. METHODS: The Korean version of the QEESI(c) was developed using a six-step approach: permission, forward translation, the first quality control, backward translation, cognitive debriefing and the second quality control, final proof reading. In order to collect data, we have done a sample survey in certain parts of Korea. A household was used as the sampling unit; we extracted random samples in each survey cluster and then interviewed two adults over 19 years of age living in each sampled household. A total of 300 subjects were recruited from the general population in local community. The factor structure in the Korean version of the QEESI was analyzed with 40 items on four sub-scales except for the 10 items in masking index using principal components analysis with Varimax rotation. A convergent validity test two sub-scales: chemical intolerance and symptom severity. We carefully compared the chemical intolerance with Nordin's chemical sensitivity scale and the symptom severity with Cho's subjective symptom score. RESULTS: The results showed that the 40 items on the four sub-scales,' chemical intolerances',' symptom severity', 'life impact', and 'other intolerances', were consistent with those reported for the US population by Miller and Prihoda. The convergent validity wes very good (r=0.4; p<0.001, r=0.5; p<0.001, respectively). A good internal consistency (Cronbach' alpha=0.86~0.96) and test-retest reliability (r=0.87~0.90) were found in all scales, except for the internal consistency in the masking index. CONCLUSIONS: The Korean version QEESI(c) showed a good reliability and validity. It should be necessary to conduct a MCS/IEI study adopting Korean version QEESI(c).