Ovarian ablation is the oldest form of systemic treatment of breast cancer and consists of removal of the main source of estrogen biosynthesis in premenopausal women. Over the last century several different means of stopping ovarian function have been studied: surgical oophorectomy, ovarian irradiation, and more recently, chemical castration by gonadotropin-releasing hormone analog therapy. In unselected patients the response rate to ovarian ablation is of about 35% but the likelihood of response is considerably higher for patients with hormonal receptor-positive tumors, the therapy being most effective in women who are actively menstruating. In spite of this evidence, the role of ovarian ablation in the management of early-stage breast cancer still remains controversial. Here we review current evidence supporting the value of this ablative procedure as an adjuvant and update ongoing clinical research to refine our knowledge about its use.