The objective of this study was to evaluate the tetrazolium test on the aleurone layer efficiency to evaluate the quality of corn seeds, hybrid Ag-304 from different harvest/threshing procedures, during storage in environmental conditions. The seeds were harvested with a moisture contents of 18.0 to 19.0%; 16.0 to 17.0% and 13.5 to 14.5% (wet basis) by the following mechanical harvest methods: threshing drum operating at 755; 585; 485 and 275rpm speed; harvested by hand followed by threshing in a stationary thresher at 500rpm; and harvest/threshing by hand. The quality seed was evaluated after 4, 8 and 12 months of storage, using the tetrazolium test on the aleurone layer; seeds with more than 75% of the colored area were considered vigorous. It was concluded that this test can efficiently be used for the differentiation of corn seed lots mechanically damaged during harvest and naturally aged during storage.