Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the salvage pathway for the biosynthesis of nicotinamide adenine dinucleotide (NAD+) from nicotinamide. NAMPT is also a cytokine that inhibits the apoptosis of neutrophils under various inlfammatory stimuli, regulates various diseases and closely associates with the progression and prognosis of cancers. However, it is still not clear whether the cytokine-like function of NAMPT is interrelated with the biosynthesis enzyme activity of NAD+. This article aims to provide novel insights for inflammation and cancers treatment by reviewing the function of NAMPT in inflammation, carcinogenesis, cancer progression and its inhibitors, APO866/FK866.