Objective: To determine the reliability of the Thai version of the Roland - Morris disability questionnaire in low back pain patients.
Material and Method: To develop Thai version of the Roland - Morris disability questionnaire and test it in 120 low back pain patients. Reliability of the Thai version of the Roland - Morris disability questionnaire was assessed by internal consistency using Cronbach’s alpha coefficient.
Results: The overall Cronbach’s alpha coefficient of the scale was 0.83. The Cronbach’s alpha coefficient of each question in the Thai version of the Roland - Morris disability questionnaire exceeded 0.7 (range, 0.71-0.93). The Cronbach’s alpha coefficient tested in acute or chronic low back pain patients whether they have back pain only or back pain with radiculopathy which also exceeded 0.7 (range, 0.83-0.87)
Conclusion: The Thai version of the Roland - Morris disability questionnaire is a reliable tool for assessing functional disability of low back pain in Thai patients.

Keywords: Thai version of the Roland - Morris disability questionnaire, Reliability, Back pain