Premenopausal women with hormone receptor-positive early breast cancer are candidates for adjuvant endocrine therapy, as recommended by the major international guidelines. To date, adjuvant endocrine options for premenopausal women include tamoxifen with or without ovarian function suppression (OFS) or an aromatase inhibitor with OFS. Multiple strategies for endocrine treatment of premenopausal women with hormone-responsive breast cancer have been assessed, and the results of randomised clinical trials have been reported over the last years. Despite this evidence, the optimal algorithm for endocrine therapy for premenopausal women with hormone receptor-positive early stage invasive breast cancer shows open questions regarding the role of OFS in addition to tamoxifen and the optimal use of hormonal agents. The panel of the Italian Association of Medical Oncology (AIOM) Clinical Practice Guidelines on Breast Cancer applied the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methodology on three critical questions on the choice of the adjuvant hormonal therapy in premenopausal breast cancer patients to summarise available evidence and to create recommendations to help physicians in their clinical practice.