The corn cultivars ?Centralmex?, ?Azteca? and ?Dentado Composto? were evaluated during two consecutive years under different harvesting periods and submitted to storage. Tests on moisture, germination, vigour, sanity, protein, ethereal extract, starch and carotenoid were carried out for each harvesting period. These tests were equally repeated at every three months after storage period. From the results obtained corn harvest is not recommended before completing 120 days from planting, mainly due to the high seed moisture content as well as for the insufficient gross protein and ethereal extract formation in the seed. Seed moisture content was reduced to 12% after a period of 6 months storage. To maintain the physical qualities (germination and vigour) acceptable, and the biochemical characteristics (protein, ethereal extract, starch and carotenoid) satisfactory, it is recommended to keep beans in hermetic tins with a relative moisture environment around 70%.