The investigation of the role of cholesteryl ester transfer protein (CETP) in lipid metabolism was divided into five main areas. These included the development of a reliable and reproducible assay for CETP activity, the development of polyclonal and monoclonal antibodies to CETP, studying the effect of various drugs on plasma CETP activity in several animal species, looking at the control of CETP secretion by different cell lines and analysing the relationship between restriction fragment length polymorphisms (RFLPs) of the CETP gene and various plasma lipid parameters in a population of 56 individuals.