The large and growing body of experimental data on biomolecular binding is of enormous value in developing a deeper understanding of molecular biology, in developing new therapeutics, and in various molecular design applications. However, most of these data are found only in the published literature and are therefore difficult to access and use. BindingDB is a public web-accessible database of measured binding affinities for various molecular types. The BindingDB allows queries based upon a range of criteria, including chemical similarity or substructure, sequence homology, numerical criteria and reactant names. The data specification includes significant experimental detail. Download poster