Behçet's disease (BD) is a chronic disorder characterized by mucocutaneous and multisystem manifestations. Fibromyalgia (FM) is characterized by widespread musculoskeletal pain and may be present concomitantly with several rheumatic diseases. Our aims were to investigate the prevalence of FM in patients with BD and to evaluate the possible relation of FM presence with BD disease activity. A total of 104 Behcet patients were included in this study. Age, sex, disease durations and the BD Current Activity Form (BDCAF) scores as disease activity evaluation were recorded. Presence of FM and the Fibromyalgia Impact Questionnaire (FIQ) scores was investigated. Also, ESR and CRP concentrations were determined in all patients. Mann-Whitney U test and Pearson's correlation tests were used for the statistical analysis. There were 60 female and 40 male patients with an age range of 19-51 years. Eighteen of 100 BD patients were diagnosed as FM. Although ages, disease duration and laboratory parameters did not differ between BD patients with and without FM, BD patients with FM were more frequently female (p < 0.000). The presence of FM did not differ significantly between patients with and without systemic manifestations. Also, oral-genital ulcers, erythema nodosum, thrombophlebitis, pustular lesions and doctor's impression of disease activity scores were not found to be different in BD patients with or without FM. However, there were significant differences in fatigue, headache, arthralgia and patient impression of disease activity (today and last 28 days) between these groups (p < 0.000; p < 0.01; p < 0.01; p = 0.021 and p = 0.027, respectively). Also, there were significant correlations between BDCAF and FIQ items that refer pain and fatigue (p < 0.01). FM is a common and important clinical problem that may represent an additional factor that worsens pain and physical limitations in patients with BD. The higher prevalence of FM in patients with BD seems to be affected by BD itself, rather than its severity.