An adult, female numbat (Myrmecobius fasciatus) was submitted to the Perth Zoo Veterinary Department for postmortem examination in November 2011. This radio-collared wild numbat had been found dead in the Dryandra Woodland, 191 km southeast of Perth, Western Australia. On external examination, the body condition was good. Three ticks (Ixodes spp.) were found on the thoracic region. The external pouch was contaminated with dirt and palpably flocculent, and the nipples oozed a purulent material. Histopathology showed widespread fibrin thrombi containing bacterial microcolonies within interstitial vessels of the mammary gland with surrounding necrotic tissue. Bacterial microcolonies were present throughout the kidney, intestine, lung, and mammary tissue, and culture produced a moderate growth of Erysipelothrix rhusiopathiae. Although erysipelas has been reported as a cause of morbidity and mortality in marsupials, this is the first report of erysipelas in the order Dasyuromorphia (marsupial carnivores) and highlights the need for ongoing surveillance for causes of disease in wild numbats and species recovery programs.