Advances in the understanding of molecular biology of cancer have allowed that in the last 30 years some biomarkers in cancer have managed to be transferred from the laboratory to clinical practice and have been established as extremely important tools in the management of breast cancer patients. In this review are presented some biomarkers that are routinely used in clinical oncology practice and have a well-established clinical value to direct treatment and establish prognosis in patients with breast cancer, such as ER-alpha (estrogen receptor alpha), PR (progesterone receptor), HER2 (Human Epidermal Growth Factor Receptor 2), Ki-67 (Marker Of Proliferation Ki-67), and other biomarkers, such as multigenic signatures, which are used more and more frequently, due to the clinical value shown in various randomized clinical trials and for being increasingly accessible in daily clinical practice. Given the considerable importance of breast cancer in public health, it is necessary to be updated with respect to current biomarkers that have a use in clinical practice and that can serve as tools to provide patients with a more personalized treatment, as well as to know their prognosis.