Phospholipid transfer protein, also known as Lipid transfer protein II and PLTP, is a secreted protein which belongs to the BPI/LBP/Plunc superfamily and BPI / LBP family. PLTP is nearly ubiquitously expressed in cells and tissues. PLTP converts HDL into larger and smaller particles. It may play a key role in extracellular phospholipid transport and modulation of hdl particles. High-density lipoproteins (HDL) play a major protective role against the development of coronary artery disease. PLTP is a main factor regulating the size and composition of HDL in the circulation and plays an important role in controlling plasma HDL levels. This is achieved via both the phospholipid transfer activity of PLTP and its capability to cause HDL conversion. PLTP is one of the key lipid transfer proteins in plasma and cerebrospinal fluid. It is involved in novel intracellular functions. PLTP is an important modulator of lipoprotein metabolism, including interparticle phospholipid transfer, remodeling of HDL, cholesterol and phospholipid efflux from peripheral tissues, and the production of hepatic VLDL. PLTP also plays an important role in inflammation and oxidative stress. Accordingly, PLTP has also been implicated in the development of atherosclerosis.