Solanum etuberosum-derived germplasm was screened for resistance to green peach aphid (GPA), Myzus persicae Sulzer, in the Red River Valley of North Dakota and Minnesota. Fifty-seven potato lines of ten BC₃ populations and forty-one potato lines of twelve BC₃ populations were screened for GPA population development in 2002 and 2003 field seasons, respectively. The impact of individual lines on green peach aphid was assessed by ranking the mean GPA per leaf into one of three categories, based on its economic threshold for seed (0-0.1 aphids/leaf) and commercial (0.2-0.3 aphids/leaf) potato production. In 2002, a third of the potato lines tested showed potential for resistance to GPA, another third showed moderate resistance to GPA while the remaining third appeared to show no resistance. As for the 2003 field study, only ten percent of the lines tested showed potential resistance to GPA.