The great majority of plasmatic lipid and lipoprotein metabolism disorders are genetically determined diseases (primary dyslipidemias). Only a minority of prevailingly severe dyslipidemias is monogenic, and a greater part of them is inherited as a polygenic trait. Analyses of the genetic background of dyslipidemia are made difficult by the complexity of lipoprotein metabolism and also by gene-gene, gene-gender and gene-environment interactions. Association studies, animal models, whole genome scans and gene expression analyses are used in the study of the genetic background of primary dyslipidemias. There are several genetically well characterized dyslipidemias (e.g. familiar hypercholesterolemia, sitosterolemia), but in most of the disorders the exact genetic cause remains unknown. The knowledge of the gene variants responsible for a particular phenotype will be essential for correct diagnosing and treatment, as well as for further development of gene therapy which brings hope for patients with severe homozygous forms of monogenic dyslipidemias.