Fibromyalgia is a syndrome characterized by chronic generalized musculoskeletal pain, accompanied by other symptoms such as fatigue, sleep disturbance and depression. Complaints of memory deficit, cognitive dysfunction, headache and gastrointestinal disorders are also common. Although it is a relatively common syndrome, exist a limited effectiveness of the pharmacologycal treatment. However, In the last years new therapeutic and diagnostic options have been sought. This scenario includes the use of different techniques of non-invasive brain stimulation, such as transcranial direct current magnetic stimulation (tDCS) and transcranial magnetic stimulation (TMS), which have already had promising results in reducing pain. Based on the above, the objective of this research is to evaluate the effect of cerebellar tDCS on clinical measures of pain and cortical excitability in patients with fibromyalgia. In this study, the intervention consists of a single tDCS session in which two devices will be used simultaneously. The active electrode will be placed in the cerebellum and/or in the primary motor cortex and the cathode in the contralateral supraorbital region. It is expected that the application of this protocol will be able to have a modulatory effect on clinical pain measures. In addition to producing changes in cortical excitability as a reflection of the integration between the cerebellum-thalamus-cortical pathways.