Odorants are volatile molecules that efficiently carry chemical information, providing one of the main ways for communicating with the environment in all kingdoms of life. In the other hand, mammalian genomes codify for hundreds of olfactory receptors (ORs), e.g. about 400 in human and more than 1000 in mouse, underlying the crucial role of the sense of smell during evolution. Therefore, the olfactory system is capable to discriminate between ~10,000 different odors. The possibility of collecting and compiling information about odorants and their receptors is thus fundamental for a functional characterization of the signaling firing event. OlfactionDB, a manually curated database providing comprehensive information for nearly 400 odorant-receptor interactions at the current state, has been developed for managing information about odorants and their receptors. OlfactionDB is a free publicly database available online from: http://molsim.sci.univr.it/OlfactionDB.