Background: Endometriosis, an inflammatory ailment with concomitant pelvic pain and infertility, is related to inflammation and hormonal imbalances. The precise pathogenesis is not established, and its treatment residues as an argue. Oxidative stress (OS) is assumed to play a chief role in the etiology of Endometriosis. Antioxidant therapy for instance vitamin E and vitamin C may have activity in lessening or constraining inflammatory markers such as interleukins 1 and 6 and monocyte-chemotactic protein-1 that may account for the release of pain inducing molecules. Objective: To evaluate the effect of antioxidant supplementation in the form of vitamins E and C in females experiencing chronic pelvic pain due to endometriosis. Subjects and methods: This study was prospective randomized controlled work that enrolled 100 endometriosis cases who attended the department of obstetrics & gynecology and its out-patient clinic, El- Hussein University hospitals during the period of research from December 2018 to December 2019.      The patients were randomly distributed into 2 groups: 50 patients were given combination of vitamin E (1200mg/day) and vitamin C (1000mg/day) for 6-8 weeks and 50 patients were given placebo pills, daily for 6-8 weeks. Results: After treatment trial, among the 50 patients on antioxidant supplementation, 20 patients (40 %) had reported reduction in menstrual cycle associated pelvic pain, “dysmenorrhea" compared to 9 out of 50 patients (18%) in the placebo group .As regard dyspareunia, results of the current work showed that after antioxidant treatment, pain with intercourse decreased in 16 women (32%) compared to four patients who only improved in the placebo group. According to dyschesia at both baseline and after therapy, result showed that after antioxidant treatment, the severity of dyschesia decreased in 16 women (32%). However in the placebo group, dyschesia improved only in two patients. As regard non-menstrual pelvic pain", 21 patients (42%) had no change in “non-menstrual pelvic pain", 24 patients showed decrease in non-menstrual pelvic pain and only 5 cases in placebo group showed improvement in the severity of non-menstrual pelvic pain. Conclusion: This study advocates that natural antioxidants as vitamin E and C at low dosages are highly efficient substitute therapy to alleviate chronic pelvic pain in females with endometriosis.