Objective: To define the sensitization pattern of patients with anaphylaxis to Vespa velutina nigrithorax (VVN). Methods: One-hundred consecutive Spanish patients with Hymenoptera anaphylaxis were studied. We systematically determined specific IgE (sIgE) to whole venoms (Vespula spp., Polistes dominula, Apis mellífera, Vespa crabro, Dolichovespula maculata) and their molecular components (rApi m 1, rApi m 5, rApi m 10, rVes v 1, rVes v 5, rPol d 5, cross-reactive carbohydrates). Specific IgE to VVN venom and its antigen-5 (nVesp v 5) were measured in a subsample. Results: Seventy-seven patients had VVN anaphylaxis. Of these, only 16 (20.8%) reported previous VVN stings but were stung by other Hymenoptera. Positive (>0.35 kU A /L) sIgE to each of the whole venoms was detected in >70% of patients (Vespula spp. in 100%). Components showing >50% positivity were rApi m 5 (51.4%), rPol d 5 (80.0%), and rVes v 5 (98.7%). This pattern was similar to that of patients with Vespula spp. anaphylaxis (n=11) but different from that of Apis mellifera anaphylaxis (n=10). Specific IgE to nVesp v 5 was positive in all studied patients (n=15) with VVN anaphylaxis and was correlated with sIgE to both rVes v 5 (R=0.931) and rPol d 5 (R=0.887). Conclusions: VVN has become the commonest cause of Hymenoptera anaphylaxis in our area. Most cases report no previous VVN stings. Their sensitization pattern is similar to that of patients with anaphylaxis to other Vespidae. Specific IgE to antigen-5 from VVN, Vespula spp., and Polistes dominula are strongly correlated in patients with VVN anaphylaxis.