BackgroundIn Iranian Traditional Medicine, mizaj (temperament) plays a key role in preventive, therapeutic and lifestyle recommendations. A reliable self-reported scale for mizaj identification is critically needed to introduce ITM into the official medical and health care system especially in the case of designing national preventive protocols.ObjectivesThe present study aimed to design a preliminary self-administered mizaj questionnaire and assessed its reliability and validity in Iran.Patients and MethodsIn this cross-sectional study, a questionnaire with 52 items was designed based on mizaj-related indices. Subsequent to content and face validity assessment, using qualitative and quantitative method, 47 items remained. Based on the non-randomly sampling, the test-retest reliability of each question and internal consistency of the questionnaire was examined by the participation of 35 volunteers. The reliable version questionnaire was filled up by 52 volunteers wherein they were divided into warm/cold and wet/dry groups based on their mizaj which was predetermined by a team of expert practitioners. Logistic regression analysis was performed for validity process between the experts’ assessment of mizaj and each of the items in the questionnaire that resulted to the final ten-item questionnaire divided into two subscales. By using ANOVA and post Hoc with Dunnet statistics, the optimum cut-off points were defined and their sensitivity and specificity was assessed.ResultsThe weighted kappa coefficients of the 39 items were between 0.40 and 0.82 showing their acceptable reliability and the Cronbach’s α coefficient was 0.71 showing the internal consistency. The sensitivity and specificity of the final questionnaire cut-off points were 65% and 93% for the warm group, 52% and 97% cold group, 53% and 67% dry group and finally 53% and 76% wet group.ConclusionsOur results suggested that many of the designed questions according to the literature’s mizaj identification indices had satisfactory reliability and the final ten-item questionnaire could discriminate the different groups of mizaj, therefore, this can be used as the first version of a brief self-report mizaj estimating scale.