During three consecutive years (1992, 1993 and 1994) trials were carried out in Sete Lagoas, Minas Gerais, Brazil, with the objective to evaluate the influence of the differents seed size and shape of two maize cultivars upon field performance. The double cross BR 201 and the open-pollinated high protein variety BR 451 seeds, were separated by shape with oblong screen 16/64? x 3/4? and different size classes with sequential round screens 24/64?, 22/64?, 20/64?, 18/64? and 16/64?. The experimental design was randomized block with six treatments (Screens 24, 22, 20, 18, 16 and 16R) and five replications. The plots sized 18,0m2 and the parameters evaluated were comprised: plant height, ear index, kernel weight per plant, grain yield, thousand seed weight, speed of germination index and field emergence. The seed size and shape did not affect the field performance and grain yield, for both cultivars. An utilization of smaller seeds could result on saving up to 44% of seeds on planting compared with the larger seeds (screen 24).