A radio-collared adult female coyote (Canis latrans) from South Carolina was found dead with no apparent signs of trauma or struggle. Necropsy revealed a ruptured aortic aneurysm within the thoracic cavity as well as severe heartworm infection, with parasites present in the caudal vena cava. Histologically, inflammatory cell infiltrates were frequent in the aneurysm and consisted of eosinophils, neutrophils, lymphocytes, plasma cells, and macrophages. Bacteria, fungi, and parasites were not found in the aneurysm. Death was due to exsanguination. This represents a first report of an aneurysm in a coyote.