A Hybridoma Data Bank (HDB) has been developed with the collaboration of ATCC (USA), Cerdic (Europe) and RIKEN (Japan). The database holds more than 23000 records of the monoclonal antibodies. HDB is designed to meet diverse research requirements. HDB describes the development, isotype, specificity, applications, availability and literature citations for an individual monoclonal antibody. The World Data Center (WDC) at RIKEN in Japan is currently giving users' access to HDB on INTERNET, packet switching system and telephone line. The procedures for access to WDC and the interactive information retrieval system in WDC are introduced. The extraction of HDB data to create the visual table, showing reactivity patterns of monoclonal antibodies, are also shown, as an example of intelligent usage of HDB.