This study was aimed to evaluate the seroprevalence of parvovirus B19 in patients with fibromyalgia syndrome (FS). Seventy-five patients with FS (44.3 +/- 8.3) and 75 healthy controls (44.2 +/- 8.1) were evaluated. Serum anti-B19 IgM and IgG antibodies were measured by ELISA technique. Patients were questioned about duration of symptoms, characteristic features of FS, and symptoms related with viral infection preceding the onset of FS. No significant difference was found regarding the prevalence of anti-B19 IgM antibodies between the groups (p=0.494). Seropositivity of anti-B19 IgG of the patients was significantly higher than control group (81.3% vs. 64% respectively, p=0.027). No statistically significant differences were found regarding to the clinical features between fibromyalgia patients with IgG antibody compared to those without IgG antibody. Parvovirus B19 IgG seropositivity was found to be significantly higher in patients with FS. Parvovirus B19 infection might have a role in the etiopathogenesis of FS or might act as a triggering factor.