We have built a database server called HorseDB which contains the genome annotation information and biological information for horse from public database entries. The aims of HorseDB are the integration of biological information and horse genome data on genome scale using bioinformatic methods. To facilitate the extraction of useful information among collected horse genome and biological data, we developed a user-friendly interface system, HorseDB; an Integrated Horse Resource and web Service. The database is categorized by the general horse information data, a sequence annotation data, and a world-wide web analysis program interface. The database also provides an easy access for user to find out the useful information within horse genomes and support analyzed information, such as sequence alignment and gene annotation results. HorseDB can be accessed at http://www.primate.or.kr./horse.