AbstractObjectiveFibromyalgia syndrome has been associated with familial clusters although the specific genetic predisposition is not clear. Accordingly, studies concerning genetic factors associated with this disease are important. Brain-derived neurotrophic factor (BDNF) has been shown to play a role in patients with fibromyalgia syndrome, particularly in mediating manifestations of pain and mood-related symptoms. Research on genetic factors, including genetic variations or single nucleotide polymorphisms, especially related toBDNFin fibromyalgia is very limited. Therefore, this study was aiming at determining the association of polymorphisms ofBDNF, particularly rs2049046 (A>T) and rs7124442 (A>G), with body mass index (BMI) and mood-related symptoms in FMS.ResultsIn fibromyalgia syndrome cases,BDNFpolymorphisms were associated with body mass index and anxiety score, specifically rs7124442 (A>G) (Fisher’s exact test χ²;p < 0.05; odds ratio (OR): 1.02) and rs2049046 (A>T) (Fisher’s exact test χ²;p < 0.05; OR: 0.55), respectively. Additionally, patients with fibromyalgia syndrome who have AA (95% CI (8.71, 11.63)) and AT (95% CI (9.32, 11.74)) alleles of rs2049046 showed higher score of anxiety compared to patients with TT (95% CI (3.98, 8.20) allele (ANOVA test;p < 0.01). These results suggest thatBDNFpolymorphisms (rs7124442 and rs2049046) are associated with body mass index and anxiety symptoms in patients with fibromyalgia syndrome.