Objective: The aims of this study were to develop a culturally adapted version of the Fatigue Severity Scale in Persian (FSS–P) and to evaluate the reliability of the FSS–P in a sample of Iranians with Multiple Sclerosis.

Materials & Methods: In this non experimental and descriptive study which was done methodologically by validity testing method, “fatigue severity scale–Persian version” was developed following a forward – backward translation procedure and cultural adaptation based on guidelines. A sample of 20 patients with Multiple Sclerosis were selected conveniently. The participants were recruited from Sina rehabilitation clinic in Tehran between 2001 to 2007. The participants were asked to answer FSS item and VAS. The FSS and VAS were readministered 3 weeks after the first visit. Test–retest reliability and internal consistency were assessed, using Intraclass Correlation Coefficient (ICC), Pearson’s Correlation Coefficient and Cronbach’s alpha, respectively.

Results: All the participants found the FSS–P item to be clear and unambiguous in a pilot testing. The ICC was reported 0.93 for the total score that showed high repeatability of (FSS) and the Cronbach’s alpha was reported 0.96.
Conclusion: The Persian version of Fatigue Severity Scale (FSS) is a culturally adapted and reliable instrument to assess fatigue in Iranian persons with Multiple Sclerosis.