Background & purpose: Mental toughness questionnaire-48 is a tool by which we can measure the level of mental toughness. Mtq48 was translated into 35 different languages and has been used. The aim of this study was to evaluate the reliability and validity of the Persian version of it.Methodology: 1064 people with age range of 14-56 years (M=25.33, SD=6), were including students, athletes, coaches and sport managers participated in this study. Forward-backward standard method with the original authors help was used to provide it’s Persian version. Face and content validity was confirmed by experts. To study the reliability of internal consistency Cronbach’s alpha was used. Also for data analysis Spss 18 and Amos 18 were used.Results: Reliability analysis using cronbach’s alpha showed overall internal reliability of the Mtq48, a=0.93 and challenge, commitment, control, emotional control, life control, confidence, confidence in abilities and confidence interpersonal were a=0.77, 0.80, 0.84, 0.78, 0.81, 0.86, 0.81, 0.81, respectively. Confirmatory factor analysis showed that the six-factor model is a good fit.Discussion: This study also found that Persian version of Mtq48 has good reliability and validity. It seems to be a suitable tool for the study of mental toughness. Thus, researchers can use Persian version of it for further research.