The organelle specific reactions that constitute the biosynthetic pathway for aminoglycerophospholipid synthesis provide an important means for examining the biochemistry and genetics of intracellular lipid transport. Biochemical studies with intact and permeabilized cells, and isolated organelles have defined some of the essential features of lipid transport between the endoplasmic reticulum and mitochondria and Golgi/vacuole. Genetic screens have now also identified mutations and genes that are involved in aminoglycerophospholipid traffic between different membranes in mammalian cells, yeast and bacteria. Increasingly, studies focused upon intermembrane lipid movement are revealing important new information about this essential aspect of membrane biogenesis.