Background: Patients with severe extraperitoneal endometriosis require rapid remission and cannot wait for the effects of oral contraceptive hormones (OCs) to appear. Case: We successfully achieved personalized gonadotropin-releasing hormone agonist (GnRHa) therapy for a patient with catamenial right shoulder joint pain and right inguinal pain associated with extraperitoneal endometriosis, which was completely unable to be suppressed by OCs. A total of 15 subcutaneous GnRHa depot injections over a period of 19 months was performed according to the serum estradiol and LH levels, in order to maintain long-term amenorrhea without any estrogen-deprivation effects. No recurrence of the catamenial symptoms has been observed for more than 35 months after the final GnRHa depot injection. Conclusion: Personalized GnRHa therapy should become the first-choice therapy for OCresistant inoperable extraperitoneal endometriosis.