Many infectious agents and parasites have been reported from the platypus (Ornithorhynchus anatinus), but most do not cause serious disease. The fungus, Mucor amphibiorum, is the only disease agent known to cause significant morbidity and mortality in the free-living platypus in Tasmania. Infection has also been reported in free-ranging cane toads and green tree frogs from mainland Australia, but not confirmed in platypuses from the mainland. This paper reviews mucormycosis in the platypus and includes the epidemiology, clinical features, mycology, pathology as well as possible surveillance, treatment and/or control modalities. The emergence and geographical spread of mucormycosis as a disease entity in Tasmanian platypuses from 1982 till 2005 are discussed. The host, agent and environment factors of the traditional epidemiological paradigm are discussed as they contribute to the conditions that lead to the selection or emergence of Mucor amphibiorum as a pathogen in a population of platypuses.