The infectious flacherie viruses are serious diseases in the silkworm, which affects the cocoon crops. However, there is only a few study on this diseases up-to-date in Korea and, in this experiment, the authors investigated the resistance of the silkworm varieties to flacherie and Ina-flacherie viruses by peroral infection. A cross, Hansaeng ＃1$ imes$ Harisaeng ＃2, showed the highest resistance to the flacherie virus a Mudeung$ imes$Geumho showed the lowest resistance among the examined varieties. It seemed that the varietal difference of resistance against Ina-flacherie virus was appeared and Jam117$ imes$ Jam118, Gyeongchu$ imes$Yeonil, Mudeung$ imes$Geumho, Hansaeng＃1$ imes$Hansaeng＃2 and Hansaeng＃3 $ imes$ Hansaeng ＃4 showed non susceptibility by peroral infection. However it was shown that Jam115 $ imes$Jam116 had the lowest resistance to Ina-flacherie virus.