The National Center for Biotechnology Information (NCBI) provides access to more than 30 publicly available molecular biology resources, offering an effective discovery space through high levels of data integration among large-scale data repositories. The foundation for many services is GenBank®, a public repository of DNA sequences from more than 133,000 different organisms. GenBank is accessible through the Entrez retrieval system, which integrates data from the major DNA and protein sequence databases, along with resources for taxonomy, genome maps, sequence variation, gene expression, gene function and phenotypes, protein structure and domain information, and the biomedical literature via PubMed®. Computational tools allow scientists to analyze vast quantities of diverse data. The BLAST® sequence similarity programs are instrumental in identifying genes and genetic features. Other tools support mapping disease loci to the genome, identifying new genes, comparing genomes, and relating sequence data to model protein structures. A basic research program in computational molecular biology enhances the database and software tool development initiatives. Future plans include further data integration, enhanced genome annotation and protein classification, additional data types, and links to a wider range of resources.