Résumé : Breast cancers arising in young women are biologically more aggressive, and most of these patients are candidates to receive aggressive treatments that include the use of chemotherapy. As most of these tumors express the hormone receptors (i.e., luminal disease), these patients are also candidates to adjuvant endocrine therapy. Chemotherapy-induced amenorrhea showed to be prognostic in young patients with luminal breast cancer. However, the role of ovarian function suppression (OFS) in addition to standard adjuvant treatments has been largely debated over the past years. Recently, several studies have provided important insights on the role of OFS. Currently, the use of tamoxifen alone without prior cytotoxic therapy can be considered a very effective treatment option in young patients with hormone receptor-positive breast cancer at low risk of relapse. On the other hand, for patients at higher risk of relapse as those who are candidates to (neo)adjuvant chemotherapy, OFS proved to be beneficial, and therefore luteinizing hormone-releasing hormone agonists (LHRHa) should be considered in addition to tamoxifen or aromatase inhibitors (AI). However, toxicity is considerable and patients should be actively engaged in decision-making. Finally, in young breast cancer patients who are candidates to (neo)adjuvant chemotherapy, loss of ovarian function and fertility may be a concern. Besides other techniques, recent results showed that temporary OFS with LHRHa during cytotoxic treatment can be considered a reliable strategy to preserve gonadal function and fertility. Despite the recent advances in the field, several gray zones remain unanswered: the role of OFS plus AI in women who remained premenopausal after 5 years of tamoxifen, the optimal extended approach in women treated with 5 years of OFS plus AI, and the role of temporary OFS with LHRHa during chemotherapy in the specific subgroup of patients with BRCA mutations and in women undergoing this strategy after prior embryo/oocyte cryopreservation.