Rabbit hemorrhagic disease (RHD) was diagnosed in domestic lagomorphs on a rabbit farm in Illinois. Clinical signs of RHD in affected rabbits included signs of depression, anorexia, fever, paddling, convulsions, and sudden death. Findings of necropsies and histologic evaluations of specimens of liver and spleen were indicative of RHD. In liver specimens obtained from dead rabbits, RHD viral antigen was detected via hemagglutination assay and viral antigen-detection ELISA. The source of the outbreak was traced to a rabbitry in Utah. As the disease spread, the outbreak involved rabbits in various regions of the United States; > 4,800 rabbits were euthanatized and buried as a result of the depopulation effort in several states. The economic impact of the disease can be considerable; if the disease is suspected, it is imperative that the appropriate state or federal veterinarian's office be contacted immediately.