To determine the prevalence of fibromyalgia syndrome (FMS) in Iraqi patients with Behcet's disease.The two-stage classification process proposed by the 1990 American College of Rheumatology (ACR) multicenter criteria committee on fibromyalgia was applied after completion of a questionnaire about Behcet's disease clinical features. Stage I: A plain questionnaire to a sample of 90 (41 female and 49 male) patients with Behcet's disease, mean age 37.5 years. Stage II: All patients with wide spread pain were examined by a physician blinded to the diagnosis of Behcet's disease for 18 tender points and 4 control non-tender points. A sample of 40 (16 female and 24 male) healthy individuals were examined as controls.There were 53 (58.9%) patients with BD with widespread pain compared to 6 (15%) individuals in the control group, whereas only 8 (8.9%) (7 female and 1 male) patients with BD fulfilled the 1990 ACR criteria for classification of FMS, compared to one individual in the controls (2.5%). There were significantly more females with BD having FMS compared to male patients. Also the FMS associated features were more prevalent in BD group compared to control group.FMS and widespread pain are more prevalent in patients with BD than in the general population while it is less prevalent when compared with other connective tissue diseases. There is a trend for an increased frequency of FMS in females with BD. BD patients with FMS may benefit from psychological evaluation as a part of their treatment.