[eng] Nowadays, cancer is one of the death causes with greater incidence on the population. Commonly, for the investigation and monitoring of cancer the most used method is the tissue biopsy, a very invasive method for the patient. Thanks to the development of new technologies to avoid invasive processes, the concept of “liquid biopsy” has born, thereby It’s possible to obtain information of the cancer through physiological fluids. In this paper we developed the different uses of liquid biopsy, the cancer biomarkers which this novel method allows us to analyze (such as circulating tumor cells or circulating tumor DNA), as well as It’s role in future advances in cancer research and improvement of therapies for the patient.