Objective: The main purpose of the present study was to evaluate psychometric properties of Persian version of WHOQOL-DIS questionnaire in elderly people with disability.

Materials & Methods A classical psychometric method was used to evaluate validity and reliability of WHOQOL-DIS questionnaire in elderly people with disability. Lawshe, and Waltz and Bausell methods were used for assessing content validity. During convenient sampling, 205 elderly, whose score in WHOQOL-DIS questionnaire was more than 4, completed the SF-12 questionnaire in order to assess convergent validity and criterion validity (using known group's comparison). Reliability was estimated using internal consistency and test-retest reliability was determined by means of Intraclass Correlation Coefficients (ICC).

Results: According to Lawshe, and Waltz and Bausell methods of content validity, acceptable scores were obtained for all items. Correlation between the WHOQOL-DIS questionnaire and the SF-12 scales was satisfactory except for social domain (P=0.13). The Intraclass Correlation Coefficients for score of questionnaire dimensions and total score was higher than 0.70. Cronbach's alpha for investigating Intraclass Correlation was higher than 0.70 except for social domain. Comparing known groups revealed distinctions in sex and health and disability status between elderly people (P<0.001).

Conclusion: In general, the findings suggested that the WHOQOL-DIS questionnaire is a reliable and valid measure of health related quality of life among elderly people with disabilities. Therefore, the questionnaire can be used in the investigation on the quality of life of elderly people.