The Oral Impacts on Daily Performance (OIDP) is a well-known oral health-related QOL instrument used internationally. The aim of this study was to develop and test a Japanese version of the OIDP for use in interviews. Following an internationally established method, the OIDP scale was translated using standardized methodology that consisted of forward translation, pilot study and backward translation. A pilot study was carried out using the revised version with 47 local residents (range, 40-105 years). In the item analysis of this study, there were no missing values or ambiguous responses. Twenty-eight percent of the participants replied that they 'had discomfort caused by an oral health problem' in the 'eating' items. Cronbach's alpha coefficient was 0.77, indicating the internal consistency reliability of the questionnaire. Denture wearers had significantly higher OIDP scores in covariance analysis with age and sex as adjustment factors (P < 0.05). Based on the results, the questionnaire was re-evaluated. A back translation was produced and approved by the original author. Further assessment and validation of this scale is needed in a study with larger sample size. (J. Oral Sci. 49, 259-264, 2007)