Reports from the 2000 and 2001 seed corn crop indicated quality problems after the seed was sized, conditioned and then planted. These problems were not predicted by the traditional measures of warm and cold germination. We suspect that damage to the seed, especially that of newer, more fragile hybrids, was occurring in the sizing of the corn seed, and that a different sizing method would result in less damage. A seed corn sizing method utilizing a flat screen sizing system was compared to conventional round cylinder precision graders, using production sized machines operating at their rated capacities. Test results showed the flat screen sizing method caused less damage to the seed, as measured by the fast green dye test, than did cylinder sizing. There were no significant trends between the two in terms of warm and cold germination. This may explain why warm and cold germination tests did not predict quality problems when the seed was planted—seed damaged in the commonly used cylinder graders was more susceptible to conditions that affected actual field germination.