Studies in cattle have demonstrated that Johne's disease can be transmitted from cow to calf in utero. Similar studies have not been carried out in sheep. Many of the current control practices in use assume that lambs are born uninfected, making it an important question to be answered. Post mortems were carried out on an infected, pregnant mob of 145 sheep on a property near Golbourn, NSW. The mob was previously screened by gel test, DTH skin test, gamma-interferon test and faecal culture. The following samples were collected from each sheep: ileocaecal valve, terminal ileum, ileocaecal lymph node, mesenteric lymph node, cotyledon, supramammary lymph node, milk/colostrum. And from the foetuses: terminal ileum (including ileocaecal valve), ileocaecal lymph node, mesenteric lymph node, blood. Tissues were collected for both histopathological examination and culture. A total of 46/145 (31.7%) ewes were culture positive, with 40/145 (27.6%) showing histopathological lesions. The foetal tissues from all infected ewes were cultured as well as controls to give a total of 80 foetuses. In addition tissues were collected from 4 pregnant, clinical cases in post mortems carried out at University of Sydney. These were added as there were few clinical cases in the mob from Golbourn. Cultures and histopathological examination of the foetal tissues is currently underway, and complete results will be discussed.