IMGT, the international ImMunoGeneTics database (http://imgt.cines.fr), is a high quality integrated information system specializing in Immunoglobulins (IG), T cell Receptors (TR) and Major Histocompatibility Complex (MHC) of human and other vertebrates, created in 1989, by LIGM, at the Universite Montpellier II, CNRS, Montpellier, France. IMGT provides a common access to standardized data, which include nucleotide and protein sequences, oligonucleotide primers, gene maps, genetic polymorphisms, specificities, 2D and 3D structures. IMGT includes several databases (IMGT/LIGM-DB, IMGT/HLA-DB, INIGT/3Dstructure-DB), Web resources ('IMGT Marie-Paule page') which comprise IMGT Scientific Chart, IMGT Repertoire, IMGT Bloc-notes, IMGT Education, IMGT Aide-memoire and IMGT Index, and interactive tools (IMGT/V-QUEST,IMGT/JunctionAnalysis). These expertly annotated data on the genome, proteome, genetics and structure of the IG, TR and MHC are of high value for comparative genome evolution studies of the adaptative immune response. (C) 2002 Elsevier Science Ltd. All rights reserved.