Whole genome sequences of more than 30 microbial species have been determined and open to the pubic since 1995. In addition, more than 100 microbial genome sequences are supposed to be disclosed or completed in a couple of years. The data are available either from the sites of groups that determined the genome sequence or from DDBJ/EMBL/GenBank International Nucleotide Sequence Databank (INSD). However, it is a daunting task for us to apply comparative genomics to the increasing number of microbial genomes. It is due to inconsistency of data format, data representation and even protocols of data annotation in the diverse data sources. Therefore, we developed Genome Information Broker (GIB) that allows us to retrieve and to display the part and/or whole genome sequences and the relevant biological annotation of all the microbial genomes together. Thus GIB will be a powerful tool for the study of comparative genomics. The URL address of GIB is http://gib.genes.nig.ac.jp.