Cancer can be characterized as a set of more than 200 diseases that have in common the capacity for disordered growth and increased invasive potential in other organs and tissues of the body. Thus, in order to better understand the nature of cancer and trace new therapies against the disease, studies have described several characteristic marks of the development of cancer, among them, cellular energy deregulation was mentioned as an emerging characteristic, being significant for the carcinogenic process and in the development of a malignant tumoral phenotype. Reprogramming tumor metabolism involves the ability of the neoplastic cell to modify, or reprogram, their metabolism to provide sufficient energy for continuous cell proliferation in cancer. Due to the relevance of metabolic reprogramming in cancer development, many studies were conducted over the past decade to better understand those mechanisms. Thus, this chapter aims to review the metabolic alterations presented by tumoral cells, as well as supply information about molecular and pharmacologic targets based on metabolic reprogramming of tumors. Furthermore, here we discuss the mechanism of action of drugs targeting metabolism that are already used in the clinic, and we point out new drugs under study. The study of metabolic alteration in cancer has shown to be an important tool for the development of therapies aimed at blocking tumorigenesis, since the tumor cell particularly depends on this pathway that is exclusively found in their biology.