BackgroundSmokeless tobacco (SLT) products are gaining popularity around the globe, particularly in Asia, Africa, and the Middle East. Among these products, Nass (aka Naswar) is popular among the Turkmen ethnicity in Iran. Although several studies reported nicotine dependence (ND) among SLT users, psychometric instruments have never been utilized to specifically measure ND among Nass users. Therefore, in this study, we aimed to evaluate the reliability and validity of the Fagerström Tolerance Questionnaire (FTQ) among Turkmen Nass users.MethodsA cross-sectional, descriptive study was conducted in June-December 2018 among 411 Turkmen adults who currently (past 30 days) used Nass. Two bilinguals (Persian English) individuals translated and back-translated the FTQ-SLT, which maintained both the questionnaire's accuracy and cultural sensitivity. Construct validity was assessed using exploratory and confirmatory factor analysis.ResultsThe mean age and standard deviation for initiating Nass were 22.5 ± 11.81 years. Exploratory and confirmatory factor analysis indicated a single-factor solution with 8-items that captured several important ND components. Using Nass frequently, soon after waking, when sick, and experiencing a craving were some of the main components. Subgroups comparison revealed that higher scores occurred among those who were married, had Nass user(s) in their immediate family, and consumed bulk form of Turkmen Nass directly without using a tissue.ConclusionOur findings show that the FTQ- SLT is a fairly reliable and valid scale to measure ND among Turkmen Nass users and warrants further testing to accommodate cross-cultural differences in other populations.