Carbohydrate-binding proteins play crucial roles across all viruses and organisms. The complex structure of carbohydrates has led to difficulties in characterising their binding and inconsistencies in how their 3D structures are reported. In order to better understand protein-carbohydrate interactions, we have developed ProCarbDB. ProCarbDB is unique in having the functional distinction between the ligand and its saccharide monomers, which is not included in the PDB. This comprehensive database of over 5100 3D X-ray crystal structures of protein-carbohydrate complexes, correctly annotates and displays the complete carbohydrate ligand, and all its interactions. Users can also select any protein residues in the proximity of the ligand to inspect not only the interactions it makes with the carbohydrate, but also with other protein residues. Where available, additional curated information on the binding affinity of the complex, and the effects of mutations on the binding, has also been made available. We believe that ProCarbDB will be an invaluable resource for understanding these crucial interactions.