Tamoxifen is the standard of care in the adjuvant treatment of premenopausal women with estrogen receptor-positive (ER+) breast cancer. Ovarian suppression (OS) is another method of endocrine therapy and has been shown to decrease the risk of recurrence and confer a survival advantage when used as the sole source of hormone therapy. However, there is no evidence that OS is superior to treatment with tamoxifen. Studies comparing OS with or without tamoxifen compared with chemotherapy have demonstrated comparable effects. There does not appear to be any additional benefit when OS is combined with chemotherapy, although there is a suggestion that there may be an effect in the subgroup of young women (aged younger than 40 years) who are least likely to experience chemotherapy-induced cessation of ovarian function. Interpretation of existing data is hampered by the lack of studies incorporating modern chemotherapy regimens and the absence of molecular analyses that would allow us to better define populations most likely to benefit from endocrine therapy. Last, the role of aromatase inhibitors (AI) in the premenopausal setting remains undefined. Two recent studies, SOFT and TEXT, aim to shed light on the effect of OS and AI in premenopausal ER+ breast cancer and are pending analysis.