The theory that the rapid depopulation of Indigenous people post-colonisation was largely caused by European introduced or exotic disease to which Indigenous people had no immunity resonates through most narratives of the early years of colonisation. The question of whether this narrative is based on sound medical evidence or is better placed in the realm of myth is the subject of this paper. Here I contend, that introduced disease is little more than a convenient explanation of the rapid depopulation of Indigenous people in south eastern New South Wales during the nineteenth century, and one that allows the illusion of colonial ethnography to perpetuate a widespread belief that introduced diseases and immunity were the unfortunate, but unavoidable cause of most Indigenous population decline. But what is the evidence that these disease theories found in Australian history are anything more than Eurocentric constructions? An Indigenous approach to the topic, as undertaken in this paper, raises questions that are as yet without answers and which challenge conventional theoretical explanations.