Cancer of the breast represents in Tunisia and the most frequent female cancer in the world. Hormonotherapy is one of the main weapons of the medical treatment based on the blockage of hormonal action on the cellular growth. Endocrine therapy remains an essential part of treatment in both adjuvant and metastatic settings and is guided by the presence and degree of expression of estrogen receptor (ER) and progesterone receptor (PgR). Adjuvant 5-years tamoxifen (TAM) is still the standard therapy for postmenopausal ER and/or PgR positive women. In premenopausal women and in adjuvant setting, medical castration by LH-RH analogues plus Tamoxifen in addition to chemotherapy improve the prognosis. All these data arose from the successive meta-analyses done showing a benefit from hormonotherapy for patients with positive HR in term of survival, disease-free survival, loco-regional and distant relapse rate. In metastatic disease, the position of tamoxifen is presently in competition with the third generation antiaromatases that seems to be equally active as tamoxifen opening the way for its use for the future in adjuvant situations.