Field and pot experiments were carried out between 1998 and 2000. The factors of the 1st order were faba bean and white lupine varieties, and the factors of the 2nd order were doses of laser irradiation. Seed irradiation was carried out using an apparatus equipped with a helium-neon laser. The seed treatment with laser light favourably influenced both the sprouting and shooting stages of the white lupine and the faba bean and modified the course of the individual phases of the plants' development. The result of these changes was accelerated flowering and plant maturity in the pot experiments, and accelerated drying out of those plants in the field experiments. Seed irradiation caused an increase of leaf surface area – the largest occurring in the period of intensive plant growth from the 2-3 leaf phase to full flowering. Irradiation of the sowing material influenced seed yield positively in the leguminous plants studied. An increase in yield was the effect of the increased pod complement of the plants in the field experiments and also of a decrease in plant losses during vegetation. The 1000 seed weight and the number of seeds per pod did not undergo any significant changes. The effectiveness of the treatment applied in the different individual study years relates the effects of irradiation to weather conditions.