Created by Marie-Paule Lefranc from Universite Montpellier, the international ImMunoGeneTics (IMGT) information system® "is a high-quality integrated knowledge resource specializing in immunoglobulins (IG), T cell receptors (TR), major histocompatibility complex (MHC) and related proteins of the immune system of human and other vertebrate species." The site contains sequence databases, genome and structure databases, web resources, and other interactive tools. With hundreds, if not thousands, of alleles and genes represented in the databases, the site is a resource packed full of information. Visitors to the highly organized site can search databases by PDB code or protein name, receptor description, or gene or chain type and species. This great site will definitely be of use to researchers, students, and instructors of genetics.