AIM: To evaluate the clinical effectiveness and safety of generic and branded dienogest in the treatment of endometriosis. so as to provide the basis for clinical use of dienogest. MEHTODS: The data of patients admitted to Third Affiliated Hospital of Zhengzhou University from August 2022 to August 2023 who received dienogest (2 mg/d, orally, for 6 months) for treatment of endometriosis were collected. The clinical efficacy and adverse reactions of generic drugs and original drugs in the treatment of endometriosis-related pain were compared through follow-up surveys of the two groups of patients at 3 months and 6 months respectively. RESULTS: There was highly significant reduction in pelvic pain in both groups with mean of similar in generic group (34.0±3.0) mm and branded group (34.5±3.9) mm. The most frequent drug-related adverse effects in generic dienogest was vaginal bleeding (93%) which was no statistical difference with branded dienogest (90%). CONCLUSION: The generic and branded dienogest have the same clinical effectiveness and similar safety.