More than 80% of the cholesteryl esters (CE) found in human plasma derive from the reaction of lecithin: cholesterol acyl transferase (LCAT). Since the content of CE in plasma high positively correlates with the incidence of atherosclerosis and myocardial infarction, there has been in the past and still is great interest in investigation of the enzymes involved in lipoprotein metabolism. This overview summarizes some general features, with particular emphasis on investigations carried out in our laboratory: (a) the substrates of LCAT in plasma; (b),the influence of LCAT on the lipoprotein spectrum; (c) the distribution of formed CE after the action of LCAT; (d) the impact of eholesteryl ester transfer/exchange protein (CETP) on lipoprotein metabolism.