Silage productivity and resistance to rice black streaked dwarf virus (RSDV) of six Korean-improved and six US introduced corn genotypes were tested in the southern part of Korea. There was a negative correlation between culm length retarded by RBSDV and coefficients of variance of culm length. Frequency distribution of culm length could be classified as three genotypic groups according to the type of distribution and percentage of RBSDV diseased plants. There were negative correlations between percent RBSDV diseased plants at harvest and culm length, percent ear bearing plants, silage yield, or ear yield, but percent RBSDV diseased plants did not related to the ear/silage ratio and stover yield. Silage yield of Pioneer XCF38 was highest, but that of Suweon 89 and NC 6131 was lowest. However, there was not signi-ficant difference in silage yield among the remaining genotypes. Pioneer XCF38, Suweon 89, and Jinjuok were quite resistant to RBSDV, but Suweon 19, Kwangok, Hoengseongok, Jecheonok, and Pioneer 3424 were susceptible and NC 6131 was most susceptible to RBSDV. Although Jinjuok and Suweon 89 were resistant to RBSDV, silage yield was not high because of early senescence of leaves after silkillg.