Introduction: Due to the fact that incorrect physical postures of clinical workers during work are directly related to pain in various areas, including low back pain, therefore, it was necessary to design a valid and reliable questionnaire. Therefore, the purpose of this study was to design and psychoanalyze a questionnaire of knowledge, attitude and behavior of medical staff about low back pain. Methods: The present study is of psychometric type and was conducted in two parts of questionnaire design and its validity and reliability in 2020 in Lorestan province. In this study, the tool used was a questionnaire to assess knowledge, attitude and behavior, which was designed using scientific sources, studies and expert opinions. To evaluate the content validity, the content validity ratio and the content validity index were used using the opinions of 10 experts. Test-retest methods were used to evaluate the internal reliability and Cronbach's alpha was used to evaluate the external reliability. Results: The designed questionnaire contains 40 items that measure 16 items of knowledge domain, 10 items of attitude domain and 14 items of behavior domain, respectively. The content validity ratio and content validity index were determined to be 0. 95 and 0. 90, respectively. Also, Cronbach's alpha of the whole questionnaire was 0. 86 and the correlation coefficient between the items in the first and second series was reported to be 0. 94. Conclusions: The present study showed that the designed questionnaire has good validity and reliability and can be used to assess the knowledge, attitude and behavior of medical staff to prevent low back pain.