The IMGT/HLA database, established in 1997, provides a centralized resource for the HLA system, which is located on human chromosome 6 and contains over 220 genes. The database is maintained by the WHO Nomenclature Committee for Factors of the HLA System and includes highly curated HLA sequences. The first release contained 964 sequences, with the most recent release containing 3300 sequences. The database is updated every three months and includes all publicly available sequences officially named by the WHO Nomenclature Committee. The database provides tools for sequence alignment, allele queries, and sequence searches, as well as information on HLA alleles, including their official designations, previous names, and the source of the sequence. The database also includes data from the HLA Dictionary, which provides serological equivalents of HLA allotypes. The database is used by the clinical HLA community for transplantation and tissue typing, and provides detailed reports on HLA alleles, including genomic and nucleotide sequences. The database has been updated with new tools, including a 'Probe & Primer Search Tool' for identifying primer and probe sequences. The database also supports data format standards for HLA information exchange between reference databases, HLA typing laboratories, and commercial typing-kit manufacturers. The database is also working with groups like ENSEMBL, EMBL-Bank, and UniProt to help define HLA references to suit all parties at different levels through the development of Locus Reference Genomic Sequences (LRGS). The IMGT/HLA database is a valuable resource for the HLA community, providing a centralized repository of HLA sequences and information. It has been used by over 7500 visitors per month in 2008, with the number of sequences increasing from 964 to over 3300. The database continues to grow, with over 450 new alleles named each year. The database is maintained by the Anthony Nolan Research Institute and is available online at http://www.ebi.ac.uk/imgt/hla/.The IMGT/HLA database, established in 1997, provides a centralized resource for the HLA system, which is located on human chromosome 6 and contains over 220 genes. The database is maintained by the WHO Nomenclature Committee for Factors of the HLA System and includes highly curated HLA sequences. The first release contained 964 sequences, with the most recent release containing 3300 sequences. The database is updated every three months and includes all publicly available sequences officially named by the WHO Nomenclature Committee. The database provides tools for sequence alignment, allele queries, and sequence searches, as well as information on HLA alleles, including their official designations, previous names, and the source of the sequence. The database also includes data from the HLA Dictionary, which provides serological equivalents of HLA allotypes. The database is used by the clinical HLA community for transplantation and tissue typing, and provides detailed reports on HLA alleles, including genomic and nucleotide sequences. The database has been updated with new tools, including a 'Probe & Primer Search Tool' for identifying primer and probe sequences. The database also supports data format standards for HLA information exchange between reference databases, HLA typing laboratories, and commercial typing-kit manufacturers. The database is also working with groups like ENSEMBL, EMBL-Bank, and UniProt to help define HLA references to suit all parties at different levels through the development of Locus Reference Genomic Sequences (LRGS). The IMGT/HLA database is a valuable resource for the HLA community, providing a centralized repository of HLA sequences and information. It has been used by over 7500 visitors per month in 2008, with the number of sequences increasing from 964 to over 3300. The database continues to grow, with over 450 new alleles named each year. The database is maintained by the Anthony Nolan Research Institute and is available online at http://www.ebi.ac.uk/imgt/hla/.