Objective: To describe the management of a patient with a pituitary adenoma secreting follicle-stimulating hormone (FSH) associated with ovarian hyperstimulation who was treated with a gonadotropin-releasing hormone (GnRH) antagonist. Design: Case report. Setting: University teaching hospital. Patient(s): A woman of reproductive age with secondary amenorrhea and ovarian hyperstimulation due to a pituitary adenoma secreting FSH, which persisted after transsphenoidal surgery. Intervention(s): Clinical treatment with a GnRH antagonist. Main Outcome Measure(s): A decrease in serum estradiol levels. Result(s): During the treatment period, ovarian hyperstimulation decreased as shown by a reduction in estradiol levels and an improvement in the patient's clinical condition and in the ultrasonography parameters. Conclusion(s): The GnRH antagonist was found to be effective for the short-term treatment of ovarian hyperstimulation secondary to a pituitary adenoma secreting FSH, thus representing a therapeutic option that should be taken into consideration in such cases. (Fertil Steril (R) 2012;97:231-4. (C) 2012 by American Society for Reproductive Medicine.)971231234