The IPD-IMGT/HLA Database is a comprehensive resource for human leukocyte antigen (HLA) sequence data, containing over 25,000 allele sequences for 45 genes located in the human Major Histocompatibility Complex (MHC), the most polymorphic region of the human genome. The database provides a stable, user-friendly repository for HLA variant sequences, essential for successful transplantation. It has been updated with new tools and methods to handle the increasing number of submissions and complex sequences. The database is maintained by the Anthony Nolan Research Institute and the European Molecular Biology Laboratory, and it serves as the official repository for the WHO Nomenclature Committee for HLA factors. The database receives submissions from over 46 countries and has processed over 53,410 submissions since its launch in 1998. The IPD-IMGT/HLA Database includes tools for sequence alignment, allele queries, and sequence search, and provides data in various formats such as FASTA, PIR, and MSF. It also offers access to an FTP site and a GitHub repository for data retrieval. The database is continually updated to reflect new discoveries and to support the increasing complexity of HLA sequence data. The database faces challenges in maintaining high-quality data curation and providing tools for analysis and visualization of full gene sequences. The database also supports the integration of new sequencing technologies, such as next-generation sequencing, which has led to an increase in the number of full-length gene sequences submitted. The database is essential for research into the generation, maintenance, and growth of HLA polymorphism, and it provides a platform for both clinical and genomic studies. The IPD-IMGT/HLA Database is a critical resource for the scientific and medical community, providing access to a vast amount of HLA sequence data.The IPD-IMGT/HLA Database is a comprehensive resource for human leukocyte antigen (HLA) sequence data, containing over 25,000 allele sequences for 45 genes located in the human Major Histocompatibility Complex (MHC), the most polymorphic region of the human genome. The database provides a stable, user-friendly repository for HLA variant sequences, essential for successful transplantation. It has been updated with new tools and methods to handle the increasing number of submissions and complex sequences. The database is maintained by the Anthony Nolan Research Institute and the European Molecular Biology Laboratory, and it serves as the official repository for the WHO Nomenclature Committee for HLA factors. The database receives submissions from over 46 countries and has processed over 53,410 submissions since its launch in 1998. The IPD-IMGT/HLA Database includes tools for sequence alignment, allele queries, and sequence search, and provides data in various formats such as FASTA, PIR, and MSF. It also offers access to an FTP site and a GitHub repository for data retrieval. The database is continually updated to reflect new discoveries and to support the increasing complexity of HLA sequence data. The database faces challenges in maintaining high-quality data curation and providing tools for analysis and visualization of full gene sequences. The database also supports the integration of new sequencing technologies, such as next-generation sequencing, which has led to an increase in the number of full-length gene sequences submitted. The database is essential for research into the generation, maintenance, and growth of HLA polymorphism, and it provides a platform for both clinical and genomic studies. The IPD-IMGT/HLA Database is a critical resource for the scientific and medical community, providing access to a vast amount of HLA sequence data.