The Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) supports scientific research and education by providing an essential resource of information about biomolecular structures. As a member of the Worldwide Protein Data Bank (wwPDB), the RCSB PDB curates and annotates the data about the experimentally determined three-dimensional structures of proteins and nucleic acids that are deposited into the PDB archive. The RCSB PDB also provides online resources to access the data in the archive, including a relational database supporting simple and complex query and reporting, visualization tools, structure-sequence comparison tools, access to the associated literature, and educational services. In the 11 years (1999–2010) since RCSB PDB has been in operation, the amount of data in the archive has increased six-fold, along with an increase in the complexity of structures being determined and in the number of experimental methods used. The evolution required by RCSB PDB to meet these challenges provides insight into the motivation and challenges of developing and maintaining a major biological resource, particularly the one used in understanding the molecular details of living systems in both normal and disease states. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 782–789 DOI: 10.1002/wcms.57