Splenic marginal zone lymphoma (SMZL) is a rare chronic B lymphoproliferative disease, whose molecular pathogenesis is still not well established. For the first time a proteomic approach was undertaken to analyse the protein profiles of SMZL tissue. Western blot, immunohistochemical analysis and functional data mining were also performed in order to validate results, classify proteins, and explore their potential relationships. We demonstrated that SMZL is characterized by modulation of proteins related to energetic metabolism and apoptosis pathways. We also reported specific proteins (such as biliverdin reductase A, manganese superoxide dismutase, beta-2 microglobulin, growth factor receptor-bound protein 2, acidic leucine-rich nuclear phosphoprotein 32 family member A, and SET nuclear oncogene) directly involved in NF-kBand BCR pathways, as well as in chromatin remodelling and cytoskeleton. Our findings shed new light on SMZL pathogenesis and provide a basis for the future development of novel biomarkers.