Abstract:Transgenic clones of potato ( Solanum tuberosum L.) cultivars "Favorita" and "Tiger head" expressing dual potato vires Y (PVY) and potato leaf roll virus (PLRV) coat protein genes were inoculated with PVY and PLRV either by mechanical robbing or by vimliferoux Myzus persicae Sulz. After inoculation the symptom development was observed and the vires liter was detected with DAS-ELISA. Results showed that the transgenic clones displayed slight or no symptom. The average PVY and PLRV liters in the transgenic clones were lower than the untransformed plants. Six of the 9 "Favorita" transgenic clones had reduced average PVY liters were about 52.5% ~ 90.0% lower than that in untmnsfonned plants. Similady, 4 of the 7 "Tiger head" transgenic clones had reduced average PLRV titers 53.0% ~ 98.0% lower than that in the untmnsformed plants. Four transgenic clones of "Favorita" and 3 transgenic clones of "Tiger head" were resistant to both PVY and PLRV infection. Some highly resistant to PVY and PLRV transgenic plants were obtained in both transgenic cultivars.