The response to lipid-lowering drugs is modified by a number of factors like age, gender, concomitant disease and genetic determinants. Even within homogenous groups of patients, individual responses vary greatly. Until now, no clinical or biochemical parameter exists which predicts whether a subject will respond well to a particular lipid-lowering drug or, in the extreme case, will develop adverse, life-threatening effects (e.g., myositis or rhabdomyolysis). The recent advances in the human genome project promises to have a great impact on our understanding of lipid and lipoprotein metabolism and of the individual response to lipid-lowering drugs. Monogenetic disorders of the lipid metabolism produce severe clinical phenotypes, such as Tangier disease, but have a minor role in the evaluation of cardiovascular risk in the general population. On the other hand, several polymorphisms in genes involved in lipoprotein metabolism (e.g., apolipoprotein E) are associated with the plasma levels of lipoproteins, explaining a substantial fraction of the variance of LDL or HDL concentrations. In combination, the knowledge of these polymorphisms, further variants yet to be discovered and variants within the genes involved in the metabolism of lipid-lowering drugs will in the future allow these drugs to be selected according to the patients needs and thus increase both efficacy and cost-effectiveness of lipid-lowering regimes.