The availability of genome sequences is revolutionising the fields of bacteriology and infectious diseases. By mid-2007, 479 bacterial genomes from 352 distinct species have been sequenced, including representatives of all notable human pathogens. Additionally, the genomes of several strains from each of 55 species have been sequenced. This tremendous amount of genomic data has led to unprecedented advances in pathogen diagnosis, genotyping, detection of virulence, and detection of resistance to antibiotics. We review current achievements in these fields and potential developments in the future for the clinical microbiology laboratory.