High-throughput and automated techniques (mass spectrometry in particular) allow increasingly rapid structural analysis of complex glycans. Information concerning the primary structure (composition, sequence and linkages), three-dimensional structure (including dynamics) and interactions of glycans is now available in sufficient quantity to justify the maintenance of databases and search facilities. Several such resources (both commercial and open access) are now available as web tools. To derive the full value of glycan databases, it will be necessary to develop a universally accepted machine-readable structural representation of glycans.