The Genome Reviews database provides up-to-date, standardized, and comprehensively annotated views of the genomic sequence of organisms with completely deciphered genomes. Currently, Genome Reviews contains information about the genomes of archaea, bacteria, and selected lower eukaryotes. Expansion to viral genomes and additional eukaryotes is planned. Genome Reviews is available for download in relational and flat file formats. In this paper, the rationale behind the creation of Genome Reviews, the approach taken in standardizing the data and its representation, and particular issues encountered in doing so are described.