The effect of light and seed rinsing during the germination of lentil seeds (Lens culinaris var. Vulgaris cv. Magda-20) on trypsin inhibitor activity (TLA) has been studied. TLA decreased progressively during germination, while hydration grade and light exposure had less influence on TIA. In general, there was no significant change in TLA after 3 days of germination, except when seeds were rinsed only once and the experiment was conducted in the dark, showing a 10% TLA decrease. Six-day germination produced TLA decreases from 7% to 18%. In this case, the number of rinses had no significant effect on the final TLA, but the activity of protease inhibitors was significantly higher in seeds illuminated for 6 h per day. Maximal TLA decreases were found in seeds germinated in darkness and rinsed daily. Under these optimum conditions, TLA first decreased slowly (12% loss of this activity after 6 days) followed by a faster decrease (up to 45% of control seeds values) after 10 days of germination. Peer reviewed