The majority of the sequence for the human genome is now available. Regardless of the researcher's area of interest, it is quite likely that they will want to use some aspect of this data. This unit helps researchers achieve that goal. It presents the gene models available at NCBI, the UCSC Genome Browser, and Ensembl. It reviews the features and options available from the three web sites to query, display, and download the data. In addition, the unit illustrates how to query each of the databases in order to identify information, such as the genomic location of a novel cDNA, a BAC clone that contains a particular gene, and homologous human genes to a particular protein sequence from a different organism.