The identification of biomarkers in patients with pharmacoresistant epilepsy could improve diagnosis and decrease time to efficient surgical treatment. In this context, we worked with three microRNAs which are candidates to used as biomarkers (hsa- mir23a, hsa-miR-31, hsa-miR-134) and applied the technique of quantitative PCR assays in plasma samples. Our results indicated that hsa-miR-31 is down-regulated in patients with refractory epilepsy, making it a promising biomarker.