Resistance to the Russian wheat aphid, Diuraphis noxia (Mordvilko), (RWA), has been identified in 109 barley accessions from the National Small Grains Germplasm Collection and 109 resistant lines have been selected from these accessions. These lines were identified, selected, and purified via screening of seedlings in greenhouse flats. Resistance measured as grain yield and yield components was confirmed to hold throughout the life of the plant when a subsample of RWA-resistant lines with differing levels of resistance were grown in the greenhouse under constant RWA pressure from seedling to maturity, and also in the field under artificial RWA infestation for two years in Wyoming. Resistant lines were not significantly affected by RWA feeding, moderately resistant lines were moderately affected depending upon the presence of other natural stresses, and moderately susceptible and susceptible lines were severely affected. Resistance measured in terms of impact on malting quality was inconclusive. The unadapted resistant lines had such poor quality that any reduction in malting quality was hard to measure by normal malt testing procedures. A new field test was designed to test for RWA feeding affects on both agronomics and malting quality of adapted RWA-resistant lines developed by USDA-ARS in Aberdeen, Idaho in cooperation with USDA-ARS in Stillwater, OK . This test involved two locations: Aberdeen, ID and Ft. Collins, CO, with the cooperation Colorado State University. Plots were either aphid-free or artificially infested at either an early or late date. Agronomic data from one year generally indicated no significant effect of RWA feeding on the unadapted resistant check and adapted resistant lines developed from that resistant check while an adapted moderately resistant line as well as the susceptible checks were severely affected by RWA feeding. RWA effect on malting quality followed similar trends but will not be reported here in detail.