All the mammalian cells should require some machinary for the intracellular transport, and it seems essential to elucidate the mechanisms underlying this transport system in order to understand the functions of lipids. However, little is known about their mechanisms, possibly because of lack in the appropriate experimental techniques. Recently, the pathogenesis of some genetic diseases which originate from the defect of intracellular transport system have been elucidated, and these studies provides us important information on the physiologic role of lipid transport system. Here, recent progress on the intracellular lipid transport system, especially those of cholesterol, fatty acid, vitamin E and phospholipids are described.