Fibromyalgia (FM) is a condition characterized by chronic widespread pain and generalized tenderness, accompanied by fatigue, sleep disturbances and cognitive difficulties. The diagnosis is merely clinical, as no confirmatory objective method is available so far. Several types of muscle abnormalities have been reported in FM, at tissue, cellular and subcellular level, that could eventually alter the resistivity of the muscle. In this paper, we used electrical impedance myography to detect changes in the passive electrical responses of muscle in a group of subjects with Fibromyalgia (n=24) and a control group without it (n=21). The overall apparent muscle resistivity obtained (2,08 ? m) is well in the range reported in the literature for longitudinal measurements. We calculated and compared brachial apparent resistivity at the lowest frequency measured by the equipment (5 kHz) between both groups and we also compared resistivity against algometric results. No statistical significant differences were found between the two groups.