Abstract Background Fenugreek is a legume plant used as an ingredient of curry spice. Incidents of IgE-mediated food allergy to fenugreek have been reported. Coincidence with allergy to peanut, a major food allergen, seems to be common suggesting a rather high rate of cross-reactivity. Objective Characterization of fenugreek allergens using patient sera and mass spectrometry-based proteomic analysis. Methods Allergenic fenugreek proteins were detected by immunoblotting, using sera from 13 patients with specific IgE to peanut and fenugreek. IgE-binding proteins were analyzed by peptide mass fingerprinting and peptide sequencing. Results A fenugreek protein quintet in the range from 50kDa to 66kDa showed high IgE-affinity, the protein at 50kDa reaching the strongest signals in all patients. Proteomic analyses allowed the classification of several fenugreek proteins to a number of allergen families. Fenugreek 7S-vicilin and 11S-legumin were partly sequenced and revealed considerable homologies to peanut Ara h 1 and Ara h 3, respectively. The presence of a fenugreek 2S albumin and pathogenesis-related (PR-10) plant pollen protein was assumed by database searching results. Conclusion In this study, individual fenugreek proteins were characterised for the first time. Observed homologies to major peanut allergens provide a molecular explanation for clinical cross-reactivity.