Hypothesis: What is the best modulation of pulse frequency in transcutaneous electrical nerve stimulation in dysmenorrhea? Purpose: To determine the effect of hypoalgesia frequency modulation pulse by transcutaneous electrical nerve (TENS) in dysmenorrhea. Methods: A controlled clinical study and prospective developed at the School of Physiotherapy Clinic / UFPI. Forty students were randomized into four distinct groups of the modulation frequency TENS: group 1 - 100 Hz, 100μs, group 2 - 4 Hz, 100μs, group 3 - placebo (apparatus off), group 4 - placebo induced (2 Hz, 40μs). All were initially evaluated by a questionnaire developed for the study, the visual analogue scale (VAS) (before, after 20, 30, 40, 50, 60 minutes) and the McGill Pain Questionnaire (before and after 20 minutes). The total duration of TENS application was 20 minutes and all protocols were performed in a single session. The analysis of variance (One-way ANOVA) followed by the Tukey procedure was applied to identify differences between experimental groups for each variable analyzed. The level of significance was p< 0,05.