Objective: To review the use of radiotherapy for relieving the symptoms of recurrent endometriosis caused by functioning ovarian remnants. Design: Retrospective study (case report). Patient(s): A woman with recurrent endometriosis of 14 years' duration. Intervention(s): After hysterectomy and bilateral oophorectomy, hormonal management, and multiple explorations for recurrent endometriosis, cycling ovarian remnants were confirmed histologically. Pelvic irradiation was used to ablate this tissue. A dose of 15 Gy in 10 daily fractions was given through anterior and posterior opposed fields using 18-mV photons. Result(s): The patient had a prompt increase in FSH levels associated with castration levels of serum E2. A review of the literature on the use of radiotherapy in this clinical situation is presented. Conclusion(s): Radiotherapy should be considered in selected patients when ovarian castration is not a viable surgical option and hormonal therapies have failed.