The aims of the present study were to inquire into the prevalence of fibromyalgia syndrome, to assess nonarticular tenderness, to measure fibromyalgia syndrome-related symptoms, quality of life, and functional impairment among posttraumatic stress disorder (PTSD) patients as compared with control subjects. Furthermore, the differences between the PTSD patients with and without fibromyalgia syndrome were studied. Twenty-nine PTSD patients and 37 control subjects were assessed as to the diagnosis of fibromyalgia syndrome according to the American College of Rheumatology. Tenderness was assessed manually and with a dolorimeter. Fibromyalgia syndrome-related symptoms, quality of life, physical functioning, PTSD symptomatology, and psychiatric features were assessed by valid and reliable self-report inventories. Results showed that the prevalence of fibromyalgia syndrome in the PTSD group was 21% vs. 0% in the control group. Furthermore, the PTSD group was more tender than the control group. PTSD subjects suffering from fibromyalgia syndrome were more tender, reported more pain, lower quality of life, higher functional impairment and suffered more psychological distress than the PTSD patients not having fibromyalgia syndrome. It is suggested that previous reports on diffuse pain in PTSD in fact described undiagnosed fibromyalgia syndrome. The link between psychological stress and pain syndromes is emphasized.