Mucor amphibiorum, a fungus previously found in captive amphibians in Europe and the platypus in Australia, was observed in free-ranging toads, Bufo marinus, in Australia. In tissues the fungus occurred as sphaerules 4.9 to 36.4 μm in diameter; hyphae were not formed. Some sphaerules developed two to 11 daughter sphaerules internally and these were released into tissues by dissolution of the outer wall. Infected toads were found at 11 sites from nine locations in northern and eastern Australia. The overall prevalence of infection in 3,518 toads was 0.71%. Mucor amphibiorum was isolated from soil at one location.