This experiment was conducted at theForage Research Farm of the Beef and Dairy Cattle Division, National Livestock Research Institute, Songhwan in 1992 and 1995 to investigate the effects of planting time (April 15, May 11, June 5) on the growth and yield of silage com(Zea mat`s L.). In the plant height, P3144W and DK729 were taller than the others, as 301.6, and 296.3cm, respectively, and P3282 was the shortest as 247.7㎝ at the first planting time. P3144W and DK729 were taller than the others, as 303.6㎝, 281.7㎝, respectively, and P3282 was the shortest as 249.6㎝ at the second planting time. P3144W was the tallest as 276.9㎝. DK689 was the shortest as 246.1㎝ at the third planting time. The ear heights of P3144W and P3282 were 137.3 and 132.7㎝, respectively, and Suweon 19 was the shortest as 116.4㎝ at the first planting time. Those of P3144W and P3282 were as 135.9, 134.4㎝, respectively, and Suwoen 19 was the shortest as 112.1㎝ at the second planting time. P3144W was the tallest as 111.0㎝ and Suweon 19 was the shortest as 94.2㎝ at the third planting time. In the dry matter yield per ha, P3352, DK729 and P3144W were higher than the others as 18,957, 18,840, 18,743㎏, respectively, and P3282 was the lowest as 13,863㎏ at the first planting time. 64743 and P3352 were 18,183 and 17,874㎏, respectively, and Suwoen 19 was the lowest as 15,007㎏ at the second planting time. P3144W was the highest as 19,112㎏ and Suwnen 19 was the lowest as 14,793㎏ at the third planting time. The TDN yield per ha, of P3352, P3144W and DK729 were 13,552, 13,281 and 13,252㎏, respectively, and P3282 was the lowest as 9,793㎏ at the first planting time. 64743 and P3352 were higher than the others as 13,149 and 13,009kg, respectively, and Suwoen 19 was the lowest as 10,872㎏ at the second planting time. P3144W was the highest as 13,521㎏ and Suwven 19 was the lowest as 10,392㎏ at the third planting time.