Technical Abstract: Soybean (Glycine max [L.] Merr.) is the major oilseed crop in North Dakota with production concentrated in the eastern half of the state. Only one virus, Soybean mosaic virus, has been reported from soybean in North Dakota. In 2010, 200 soybean fields from 25 counties that have the majority of soybean hectares in the state were surveyed for Alfalfa mosaic virus (AMV) and Soybean dwarf virus (SbDV). AMV and SbDV have been detected infecting soybean in multiple Midwestern states and are reported to reduce yields in soybean. Fields were sampled with a grid pattern across the area with at least 8 km between fields. In each field, 20 leaves were collected at random along transects of approximately 170 m. Leaves from each field were bulked and sap was extracted in phosphate buffer and tested using double-antibody sandwich ELISA with positive controls, reagents and protocol from Agdia Inc. Using DAS-ELISA, AMV was detected in eight fields and SbDV was detected in one field. Infections were confirmed by high throughput sequencing and quantitative real-time reverse transcription polymerase chain reaction One field sample from Cass County was positive for AMV and one field sample from Grand Forks County was positive for SbDV. AMV was reported by the American Phytopathological Society Virus Working Group (2007-2008) to be widely prevalent in North Dakota, but we found no peer-reviewed reports of verified AMV identification on any crop in the state. To our knowledge, this is the first confirmed report of AMV and SbDV infecting soybean in North Dakota. Serious infestations by the soybean aphid, Aphis glycines, requiring chemical control, have occurred in recent years in North Dakota. This aphid could result in greater distribution of AMV and SbDV in soybean since it is a vector for both viruses.