Nampt/PBEF/visfatin is the rate-limiting enzyme that catalyzes the first step in NAD biosynthesis from nicotinamide and regulates growth, apoptosis and angiogenesis of mammalian cells. This enzyme was originally cloned as a putative cytokine shown to enhance the B cell precursor maturation in the presence of IL-7 and stem cell factor. A number of cancers have increased expression of Nampt/PBEF/visfatin, which regulates a variety of different signaling pathways such as PI3K/Akt, ERK1/2 and STAT3. FK866/APO866 and CHS828/GMX1777 are two known inhibitors of Nampt/PBEF/visfatin and have been evaluated as anticancer agents in the clinic. This review will focus on its role in carcinogenesis and cancer progression and its inhibitors as therapeutic target for cancer treatment.