During germination, trypsin inhibitor (TI) content increased relative to total protein and dry weight in cotyledons from two varieties of Vicia faba. These data, together with changes in total protein profiles and amounts, suggest that TI proteins are not hydrolysed in parallel with other seed proteins and dry matter. In contrast, TI content in germinating Cicer arietinum seeds remained constant during the germination period; in this case, however, substantial changes in the total protein profile were not observed. TI isoform analyses indicated that compositional changes occurred during germination in both species.