Observational Program to Assess Routine Use of Add-back Therapy in Patients With Endometriosis in Russian Federation, Planned for 6-month Course of Lucrin Depot® (Leuprorelin)

* Age from 18 to 50 years * Written Patient Consent for Use/Disclosure of Data * Diagnosis of genital endometriosis confirmed by laparoscopy (external genital endometriosis) or ultrasound (internal genital endometriosis) * Candidate for treatment with Lucrin Depot for 6-month course * Patients with suspected endometriosis suffering from chronic pelvic pain if other reasons for pain are excluded

* Contraindications to administration of Lucrin Depot (leuprorelin): * Hypersensitivity to leuprorelin similar products of protein origin or any of the excipients in drug product composition * Vaginal bleedings of unknown etiology * Hysterectomy * Pregnancy and lactation * Menopause (absence of cyclic menstrual hemorrhages for 1 year before the start of this program) * Acute infectious period, inclusive of acute inflammatory diseases of small pelvic organs * Other contraindications that make the patients participation impossible (by investigator judgment) * Previous enrollment in the present program * Extra-genital endometriosis