Objectives: To describe the anthropometric profile and body composition ofwomenfrom Southern Spain diagnosed with fibromyalgia (FM) and to compare the observed values with values from other studies conducted on FM patients and with national reference values. Materials and methods: The body composition of 104women diagnosed with FM was assessed using an eight-electrode impedance meter. The reliability of the body composition measurement was tested in a randomly selected sub-sample (n = 28). The reliability study showed a test-retest systematic error close to zero in most of the parameters studied. Results: The women with FM who were studied had ameanweight of 71.3+/-13.4 kg, height of 158+/-6 cm, body mass index of 28.6+/-5.1 kg/m(2), body fat mass of 38.6+/-7.6%, total body water of 31.6+/-3.8 l and muscle mass of 23.4+/-3.0 kg. In general, there were no substantial differences in weight and body mass index between women with FM and those analyzed in other Spanish and European studies involving FM patients, nor when they were compared with regional or national reference values. However, the prevalence of obesity in the women with FM under study was 33.7%, a higher figure than that from the national reference data for obesity in similarly aged women (i.e. 26,4%). Conclusions: The results suggest that obesity is a common condition in women diagnosed with FM, its prevalence in this population being higher than the national reference values. This study provides detailed information about the body composition characteristics of women with FM. (C) 2010 Elsevier Espana, S.L. All rights reserved.