A b s t r a c t . In this study alternating magnetic field treatments at low frequency (60 Hz) with combinations of three magnetic flux densities (20, 60 and 100 mT) and three exposure times (7.5, 15 and 30 minutes) were used as pre-sowing seed treatments in three maize ( Zea mays L.) genotypes (CL-12 X CL-11, CL-4 X CL-1 and CL-13 x CL-1). In the case of CL-12 X CL-11 genotype these treatments increased significantly the seedling eme rgence rate, seedling dry weight and emergence in soil. The best treatment was found at magnetic f lux density of 100 mT and exposure time of 7.5 min, with significant improvements in seedling emer gence rate by 123.2%, field emergence by 110% and seedling dry weight, 21 days after plantin g, by 30.1%. In the case of CL-4 X CL-1 genotype it was found a negative biostimulation for see dling emergence percentage; finally in the CL-13 x CL-1 genotype there was not any significant effec t. These results show that electromagnetic field treatment provide a simple and ecologically well co mpatible method to improve seed vigour in maize but is necessary to find the optimal irradiat ion parameters to induce a positive biostimulation in the maize seeds which also depends on the seed g enotype.