Amaranthus dubius (Amaranthaceae), often called "spleen amaranth," is one of the most popular edible leafy amaranths throughout the world. The plant was accidentally introduced to Korea Republic but currently is cultivated as a leafy vegetable. Edible young leaves and stems are cooked like spinach. In July 2019, symptoms of white blister rust were found on A. dubius on farmland in Jeongeup, Korea Republic, with a disease incidence of 70%. Symptoms appeared as light green to yellow chlorotic spots on the upper surface of the leaves. Blister sori formed on the corresponding lower surface were white, oval to ellipsoidal, and 3-4 mm in diameter. The causal pathogen was isolated and identified as Wilsoniana amaranthi based on morphological, molecular and pathogenicity analyses. The resulting sequences were deposited in GenBank (accession nos. MN526483 for ITS and MN533957 for cox2). This is thought to be the first report of white blister rust caused by W. amaranthi on A. dubius in Korea Republic.