These work had the purpose to give informational support to the producers of popcorn seeds and/or grains, to the improvement of physiological quality from popcorn seeds of cultivar CMS-43. The seeds were submitted to three degrees of mechanical exposure (no damage, with damage and with double damage) and it was evaluated for germination, vigor (eletrical conductivity) and expansion capacity. The results allowed to conclude that the germination, vigor and expansion capacity of the damaged popcorn seeds were significantly reduced. Finally, regardless the purpose of production, seeds and/or grains, the harvest of popcom must be undertaken with minimal mechanicai damage, to give a product with maximum quality.