A standardized questionnaire has not been established for screening or diagnostic assessment of patients with multiple chemical sensitivity (MCS) in Japan. In the US, Miller and Prihoda (1999a,b) developed a questionnaire that could be used internationally, the Quick Environment Exposure Sensitivity Inventory (QEESI), to assist researchers and clinicians in evaluating patients and populations for chemical sensitivity. The Japanese version of QEESI was subsequently translated by Ishikawa and Miyata (1999). The present study was performed to investigate the reliability and validity of QEESI (Japanese version) for research purposes and for evaluation of patients with MCS in Japan. A total of 498 subjects were recruited from the general population of Miyagi prefecture, Japan. The factor structure in QEESI was analyzed with 40 items on four subscales except for the items in 'Masking' using principal components analysis with Promax rotation. The results showed that 30 items on three subscales, 'Chemical Inhalant Intolerances,' 'Symptom Severity,' and 'Life Impact' except for 'Other Intolerances' were consistent with those reported for the US population by Miller and Prihoda (1999a). Cronbach's alpha reliability coefficient ranged between 0.87 and 0.94 indicating high internal consistency in the 30 items on three subscales. Next, we compared the mean scores on three subscales of QEESI in two groups: 131 self-reported MCS group who were new outpatients at the Environmental Medical Center in Kitasato Institute Hospital, and 131 members of the general population (controls) who were matched for both gender and age with the self-reported MCS group. Mean scores on each subscale for the self-reported MCS group were significantly greater than those for controls (P <0.001). Mean scores on all of the 30 items on three subscales for the self-reported MCS group were also significantly greater than for the controls (P <0.001). These findings indicated that the 30 items on three subscales in QEESI can be used for surveys and for diagnostic assessment of patients with MCS as well as for comparative studies between patients in Japan and in other countries.