To eliminate Johne's disease from an infected farm or to prevent transmission, it is essential that susceptible animals are not exposed to an environment contaminated with Mycobacterium paratuberculosis. M. paratuberculosis is capable of persisting in the environment for long periods due the high lipid content in the cell wall and the metabolic inactivity of the organism. Physical factors that could influence the survival of M. paratuberculosis in soil including temperature, pH, exposure to ultra-violet light and moisture content were investigated under controlled conditions. The experiment involved trays of contaminated soil randomised 2 x 2 x 2 x 2 x 3 factorial (48 unique treatments) featuring implied replication. Four naturally occurring soils with each combination of high or low pH and organic matter were mixed with faeces from a cow with clinical Johne's disease. The experimental temperature, moisture and ultra-violet conditions were applied to soil in individual trays and survival of M. paratuberculosis was measured by proportional recovery using double incubation and Bactec culture methods. Dry soil and high soil temperature (30ºC) were the most significant factors in reducing the recovery of M. paratuberculosis from soil. Wet and dry cyclic conditions resulted in intermediate recovery of M. paratuberculosis compared to soil exposed to either wet or dry conditions. The effect of soil pH was minor but results were confounded with soil organic matter and soil type. Ultra-violet exposure appeared to have no direct effect on survival of M. paratuberculosis in soil however summer periods of high sun exposure with consequent elevated soil temperatures and dry conditions will be most effective in reducing the persistence of M. paratuberculosis in the environment. In strategies for on-farm control of Johne's disease consideration needs to be given to farm environments where poor drainage or permanent water and shading would enhance the survival of M. paratuberculosis.