Breast cancer is the first cancer in women worldwide. Since the previous estimates of WHO in 2008, incidence is increasing and it is estimated that 30% of women will develop immediately a metastatic form. However, advances in molecular biology and the discovery of new therapies have extended significantly the survival of patients and improved the quality of life of patients with metastatic breast cancer. The study of gene expression and protein profile has resulted in a finer classification of breast cancer and adapt the treatment of patients according to their molecular profiles. The purpose of our work is to describe the different targeted therapies used in the MBC and their action's mechanism referring to various therapeutic trials described in the literature.