The level of resistance of SO barley breeding lines seedlings were tested to three aphid species Rhopalosiphum padi (L.), Rhopalosiphum maidis (Fitch) and Schizaphis graminum (Bond.) (Homoptera: Aphididae) under laboratory conditions. The present work showed that all tested genotypes were subject for infestation with the three aphid species, but at different population levels. The criterion for resistance was based on the average daily reproduction rate of the female aphids to be more or less. Only 8 genotypes were considered resistant to R. maidis and 3 to R pad. However, 7 genotypes were considered moderately resistant to Ft maidis and 3 to R. pack All genotypes were found to be susceptible to S. graminum.