Abstract-1. Adult cane toads, B. marinus, survived in salinities up to 40% sea-water (SW).2. Pre-exposure to 30, then 40% SW, increased the survival time of toads in 50% SW. 3. Plasma from toads acclimated to salt water is hyperosmotic to the environment -a result of increased plasma sodium, chloride and urea concentrations.4. When toads were placed in tap-water and 20% SW, all significant changes to plasma sodium, chloride, urea and osmotic pressure occurred within the first 2 days of exposure.5. When toads were placed in 30 and 40% SW environments, the increases in plasma sodium and chloride concentrations occurred within the first 2 days of exposure while urea and total osmotic pressure continued to rise until some time between 2 and 7 days exposure.