Objective: The present study aimed to cross-culturally adapt the modified Oswestry Low Back Pain Disability Questionnaire (ODQ) into Thai.

Material and Method: The process comprised of an initial forward translations from English to Thai, synthesis of the translations, back translation, and back translation approval. The approved version of Thai ODQ was then calculated for test-retest reliability. Forty patients with LBP, aged 40.1 ± 10.7 years, were recruited into a test-retest reliability study.

Results: The test-retest reliability, calculated by intraclass correlation coefficient, was assessed on two occasions separated by a time interval of 20-30 minutes. The values of test-retest reliability of items ranged from 0.80-1.00. The value of total score was 0.98.

Conclusion: This finding indicated good reliability of the Thai version modified ODQ.

Keywords: Reliability, Cross-cultural translation, Modified Oswestry Disability Questionnaire, Low Back Pain