The studied material covered 58 accessions representing Vicia faba of section Faba, V. bithynica of section Bithynicae and seven species of section Narbonensis. Proteins of individual seeds were separated by polyacrylamide gel electrophoresis and the gels were stained for inhibitory activity against trypsin. The number of trypsin inhibitor (TI) bands recorded in particular species varied from three in V. eristalioides and V. galilaea to 15 in V. narbonensis; in total, 30 bands were distinguished in the examined material. Except for V. eristalioides, the studied species showed intraspecific variation with respect to electrophoretic TI patterns. A statistical analysis of the data, using hierarchical UPGMA grouping, resolved the studied taxa into three main clusters. V. faba subspecies/varieties formed one cluster. The second cluster consisted of V. narbonensis varieties and the rather distantly related V. eristalioides. The third cluster comprised V. bithynica as a peripheral species and the more closely associated V. galilaea, V. hyaeniscyamus, V. johannis, V. kalakhensis and V. serratifolia. The obtained results are discussed with reference to taxonomic relationships of the species under study.