 This study is a prospective observational cohort study. The study will be conducted in routine clinical practice settings. It is planned to enroll 870 patients with endometriosis for whom a decision has been made by the physician to treat with dienogest according to local health authority approved label. It is the aim of this observational cohort study to further characterize the effectiveness of dienogest in improving quality of life and long-term safety in routine clinical practice setting. Endometriosis is chronic and progressive disease and there is unmet need for long-term treatment. Visanne with proven efficacy and safety, can be good option for long-term treatment, however, experience with Visanne beyond 15 month is limited. And long-term up to 24 months data on effectiveness and safety of Visanne would support the long-term treatment strategy for Endometriosis management in the clinical practice. 