Trypsin inhibitor activity was determined in both fresh and dry seeds of four legumes namely; broad bean, cowpea, peas and kidney bean. The obtained results showed that the values of trypsin inhibitor activity (TIA)  for all samples were higher in dry seeds than those in the corresponding fresh samples. Dry kidney bean had the highest level of TIA (13.90 TUI/mg) followed by cowpea (12.6 TUI/mg) and pea (9.10 TUI/mg). Germination of the legume seeds resulted in progressive decrease in TIA. After 72 hrs of germination, more than 60% of TIA were declined in all samples. Extending germination period to 96 hrs, slightly affected the retained activity of trypsin inhibitor in all samples. Boiling dry faba bean seeds in water for 3 hrs, remarkably decreased TIA. The remained activity was 28% of the original TIA in the untreated sample. Boiling the other legume seeds for different periods resulted in a sharp decrease in TIA in all samples after boiling for 20 min. More than 70% of TI was inactivated, in all samples, after boiling for 60 min. Neither germination nor boiling caused complete removal of TIA. Therefore, a combination of the two treatments might be more effective.