Purpose Overactive bladder (OAB) is a clinical syndrome that is currently treated initially with anticholinergics, although some other therapeutic alternatives exist, such as neuromodulation, botulinum toxin, and posterior tibial nerve stimulation (PTNS). The purpose of this study was to assess the efficacy of PTNS in patients with OAB refractory to anticholinergics. Materials and Methods We present a cohort study of 14 women with OAB to whom we applied PTNS. We assessed (before and after the treatment) the diurnal micturitional frequency, the nocturnal micturitional frequency, urgency episodes, and urge incontinence episodes. Results were analyzed by using the Wilcoxon test for nonparametric samples. Results We observed statistically significant improvement in the diurnal micturitional frequency (p=0.05), in episodes of micturitional urgency (p=0.03), and in episodes of urge incontinence (p=0.004). A total of 50% of the patients felt subjective improvement from their pathology. Conclusions PTNS is a valid, minimally invasive treatment option with minimum morbidity for patients with OAB refractory to treatment with anticholinergics.