Fatty acid synthase (FAS) is a key bio synthetic enzyme involved in lipogenesis and the production of long-chain fatty acids from acetyl-coenzyme A (CoA) and malonyl-CoA. Uptake of glucose into cancer cells leads to the production of pyruvate via the glycolytic pathway. Pyruvate is utilized to produce ATP via the Krebs cycle in the mitochondria; in turn, acetyl-CoA, one of the products, acts as a substrate for neoplastic lipogenesis. Normal cells (except liver and adipose tissue) have low levels of expression and activity of FAS, hich is tightly regulated by diet, hormones and growth factors. However, in rapidly proliferating cancer cells, fatty acids can be synthesized de novo in order to provide lipids for membrane formation and energy production via β-oxidation and lipid modification of proteins. More evidence points towards FAS inhibition as potential therapeutic target in cancer.