The growth period of corn is so shorter than that of any other crops. So, corn is the most promising crop in upland cropping systems. However, there was not so much in basic informations related to cultivation method including seeding period. This study was undertaken to investigate how different seeding date affected the growth characteristics and yield in corn. Two corn varieties(Chalok 4, Ilmichal) were planted on 6 different seeding date(from April 11 to July 10) in upland and paddy field. The total growth period was the longest(105 days) on the seeding date of April 11 regardless of testing varieties and cultivation condition. The total growth period was ranged from 77 days to 86 days in other seeding dates. The commercial yield of corn was higher in paddy field than that of upland field. In consideration of economic productivity, it was concluded that seeding date can be possible from early in April to middle of July in middle and south plain regions.