The Integrated Microbial Genomes (IMG) system is a comprehensive resource for comparative analysis of publicly available genomes from all three domains of life, including plasmids and viruses. IMG integrates data from NCBI's RefSeq and other sources, providing detailed annotations and functional information. The system offers tools for analyzing and reviewing gene and genome annotations, with regular updates since its initial release in March 2005. IMG supports expert review (IMG/ER), education (IMG/EDU), and analysis of genomes related to the Human Microbiome Project (IMG/HMP). IMG's data content has grown significantly, with over 6,891 genomes and 11.6 million genes as of July 2011. The system includes proteomics, transcriptomics, metabolomics, and other 'omics' data, and provides tools for comparing genomes, genes, and functions. Future plans include integrating more 'omics' data and improving annotation quality through re-annotation projects.The Integrated Microbial Genomes (IMG) system is a comprehensive resource for comparative analysis of publicly available genomes from all three domains of life, including plasmids and viruses. IMG integrates data from NCBI's RefSeq and other sources, providing detailed annotations and functional information. The system offers tools for analyzing and reviewing gene and genome annotations, with regular updates since its initial release in March 2005. IMG supports expert review (IMG/ER), education (IMG/EDU), and analysis of genomes related to the Human Microbiome Project (IMG/HMP). IMG's data content has grown significantly, with over 6,891 genomes and 11.6 million genes as of July 2011. The system includes proteomics, transcriptomics, metabolomics, and other 'omics' data, and provides tools for comparing genomes, genes, and functions. Future plans include integrating more 'omics' data and improving annotation quality through re-annotation projects.