Mixed viral infections of heterologous viruses like Potato virus Y (PVY) (Potyviridae: Potyvirus) with Potato leafroll virus (PLRV) (Luteoviridae: Polerovirus) are a regular occurrence in potato systems in Idaho. An increased number of plant samples from Idaho’s potato fields in the last two years have serologically (Double antibody sandwich enzyme linked immunosorbent assay: DAS-ELISA) tested positive for both PVY and PLRV and exhibited more severe symptoms than singly infected plants. Several studies have extensively reported this mixed infection phenomenon but none has examined the influence of such infections on the vector biology and behavior. Studies were conducted to examine the effect of mixed viral infection (PVY-PLRV) on the biology and behavior of the most efficient vector Myzus persicae (Sulzer) (Homoptera: Aphididae). Single M. persicae adults were clip caged to the leaves of PVY, PLRV, PVY-PLRV infected and noninfected potato plants for 96h. Number of nymphs produced in all four treatments was recorded at 24h time interval. The fecundity of M. persicae was significantly higher on PVY-PLRV infected plants than on singly infected plants and non infected plants. Preference behavior of both winged and wingless M. persicae was studied with the help of settling bioassays. The settling patterns of winged and wingless M. persicae were consistent. Both winged and wingless M. persicae preferentially settled on PVY-PLRV infected plants than on singly infected plants and noninfected plants.