Abstract : There are various complaints or problems during menstruation that are usually experienced by a woman, but the most problem was discomfort or intense pain, this was commonly called dysmenorrhea or menstrual pain. Exercise was a non-pharmacological method to reduce dysmenorrhea pain. The purposed of this study was to examine the effectiveness of exercise modification "Kak Erfita" on reducing menstrual pain (dysmenorrhea) in adolescents. The design of this study was a quasi-experimental with the pretest-posttest control group design technique. The research subjects were adolescent at one of junior high school in South Jakarta in 2019. The results showed that there was a significant influence on the intervention group compared to the non-intervention group in cycle I with a value of p = 0.037 (p <0.05) and there was also a significant influence in cycle II with a value of p = 0.018 (p <0.05). "Kak Erfita" exercise modification to reduce menstrual pain. The more often the exercise "Kak Erfita" was carried out, the lower level of menstrual pain will be felt. Exercise "Kak Erfita" can be a routine sports activity at school to reduce menstrual pain in adolescents.