Technical Abstract: Successful selection of Russet Norkotah lines have produced larger, more vigorous vines and higher yields than the standard Russet Norkotah (RN). A significant disease, Potato Virus Y (PVY), while producing mild or “latent” symptom in this cultivar, has been shown to be significantly reduce yields. To determine PVY’s effect on yield, PVY infected RN and Russet Norkotah selection 3 (RN3) yields were compared after planting in Hermiston, Oregon in 2001, 2003, and 2006. After emergence, individual plants were ELISA tested for PVY multiple times during the growing season to confirm infection. Plants were categorized when infected; 1) current season, 2) seed borne or 3) “no PVY”. At harvest, total and marketable yield data was collected. RN3 produced higher total yields than RN, regardless of infection categories. Yield of RN and RN3 was reduced due to PVY in the following order; no PVY<<current season PVY<<seed borne PVY.