Johne’s disease in sheep and cattle is caused by Mycobacterium avium subspecies paratuberculosis, (MAP) and results in wasting and the eventual death of a proportion of infected animals in a flock or herd. The disease is economically significant especially on farms with a high prevalence of infection, as severity in individuals tends to be worse in such flocks. In the last 20 years important discoveries have significantly aided on-farm management of Johnes’ disease. In 1994 it was difficult to culture sheep strains of MAP and now it is routine. Culture which takes months is being replaced by high throughput molecular assays which can have results returned to farmers in days. Molecular assays have also led to easier identification of the different strains of MAP. Improved understanding of the routes of transmission as well as the survival of MAP in the environment has aided in management of the disease. As basic research into the disease has increased significantly, so have the investigations into the relationship between Johne’s disease and human health issues. While it is unlikely that we will be able to eradicate Johne’s disease in Australia, with increased understanding of the bacterium and it's interactions with the host, improved diagnostics, vaccines and breeding programs, control of the disease is possible.