The marine mussel innate immunity provides protection to pathogen invasion and inflammation.In this regard, the mussel hemolymph takes a main role in the animal innate response.Despite the importance of this body fluid in determining the physiological condition of theanimal, little is known about the molecular mechanisms underlying the cellular and humoralresponses. In this work, we have applied aMS (nano-LC-MS/MS) strategy integrating genomicand transcriptomic data with the aim to: (i) identify the main protein functional groups thatcharacterize hemolymph and (ii) to map the elements of innate immunity in the marine musselMytilus edulis hemolymph proteome. After sample analysis and first protein identificationbased onMS/MS data comparison, proteins with unknown functions were annotated with blastusing public database (nrNCBI) information. Overall 595 hemolymph proteins were identifiedwith high confidence and annotated. These proteins encompass primary cellular metabolicprocesses: energy production and metabolism of biomolecules, as well as processes related tooxidative stress defence, xenobiotic detoxification, drug metabolism, and immune response.A group of proteins was identified with putative immune effector, receptor, and signalingfunctions in M. edulis. Data are available via ProteomeXchange with identifier PXD001951(http://proteomecentral.proteomexchange.org/dataset/PXD001951).