The presence of Toxoplasma gondii in dasyurid marsupials has now been proven morphologically, serologically and by animal passage. Of the 240 animals examined (12 Antechinomys spenceri, 9 Antechinus apicalis, 14 Antechinus macdonnellensis, 21 Antechinus stuartii, 51 Dasycercus cristicauda, 107 Dasyuroides byrnei, 1 Sminthopsis crassicaudata, 2 Sminthopsis larapinta and 17 Sminthopsis leucopus) a preponderance of involvement of brain, spinal cord and heart has been shown. Endemic infection in Dasyuroides byrnei has been proved, but there is good evidence for infection within the laboratory which is probably caused by their diet of raw sheeps' heart, brain and liver. Infection has never been demonstrated in animals less than 6 mth of age. The 21 Antechinus stuartii examined have remained entirely free from infection despite a lengthy stay in the laboratory and a similar diet. This freedom from infection may be indicative of a specific resistance to infection by this one species of the Dasyuridae. The presence of Toxoplasma gondii in dasyurid marsupials has now been proven morphologically, serologically and by animal passage. Of the 240 animals examined (12 Antechinomys spenceri, 9 Antechinus apicalis, 14 Antechinus macdonnellensis, 21 Antechinus stuartii, 51 Dasycercus cristicauda, 107 Dasyuroides byrnei, 1 Sminthopsis crassicaudata, 2 Sminthopsis larapinta and 17 Sminthopsis leucopus) a preponderance of involvement of brain, spinal cord and heart has been shown. Endemic infection in Dasyuroides byrnei has been proved, but there is good evidence for infection within the laboratory which is probably caused by their diet of raw sheeps' heart, brain and liver. Infection has never been demonstrated in animals less than 6 mth of age. The 21 Antechinus stuartii examined have remained entirely free from infection despite a lengthy stay in the laboratory and a similar diet. This freedom from infection may be indicative of a specific resistance to infection by this one species of the Dasyuridae.