LeptoList is the reference database dedicated to the genome of Leptospira interrogans serovar Lai, the paradigm of leptospirosis causative agents (1). It has been developed as a spin-off of the B. subtilis genome project (2), GenoList provides a data schema for the management of DNA and protein sequences, combined with the relevant annotations and functional assignments (3). Information about gene functions and products is updated by a curating team. LeptoList is based on a generic relational data schema and World-Wide Web interface developed for the handling of bacterial genomes, GenoList. The underlying DataBase Management System used in the Hong Kong based databases is MySQL. The WWW interface was designed to allow users to easily browse through genome data and retrieve information according to common biological queries. LeptoList also provides more elaborate tools, such as pattern searching, which are tightly connected to the overall browsing system. LeptoList is accessible at the URL http://www.bioinfo.hku.hk/LeptoList/. Similar bacterial databases (for Bacillus anthracis, Bacillus cereus, Neisseria meningitidis, Pseudomonas aeruginosa, Staphylococcus epidermidis, Streptomyces coelicolor, Thermoanaerobacter tencongensis, Vibrio cholerae, Xylella fastidiosa, etc.) are accessible at the URL http://www.hkupasteur.hku.hk/hkuip/databases.html