Technical Abstract: Russian wheat aphid (RWA) is a new and devastating pest of barley in the western US. No resistance was found in US cultivars whether two-row, six-row, malt, feed, spring or winter. A screening of the entire collection of barley accessions in the National Small Grains Collection by the USDA-ARS in Stillwater, OK, identified 109 accessions with some level of resistance to RWA. These accessions were not adapted to US barley production practices or environments. A pre-breeding program was initiated in Stillwater to bring these resistance genes into adapted barley backgrounds that breeders could utilize in their breeding programs without negative effects on elite lines. Seventeen spring two-row malting barley germplasm lines were released to breeders involving 17 sources of resistance in four adapted backgrounds.