The influence of seed material stimulation using variable magnetic field with induction of 30 mT for 8 or 15 seconds on grain yields and on some yield structure elements of two spring wheat varieties (Koksa and Tybalt) was evaluated. Stimulation of seed material had no significant effects on spring wheat yielding. Instead, only a tendency to decrease grain yield due to stimulation could be observed. Among studied elements of yield structure, the number and weight of grains per ear significantly increased, but this did not considerably affect the grain yields. Regardless of the stimulation level, higher grain yields were achieved for cv. Tybalt. Pre-sowing seed stimulation had no significant influence on weed infestation of spring wheat canopy.