The idiopathic syndrome of cloacal prolapse was observed in the frog Litoria rheocola at 2 sites in the Wet Tropics of Australia; 1 of 365 individuals (0.3%) at Tully Gorge National Park and 5 of 92 individuals (5.4%) at Murray Upper National Park. The condition appeared to have resolved spontaneously with no clinical complications in 2 individuals at successive captures 14 and 155 d later. It was not observed in the sympatric frogs L. genimaculata (n = 206), L. nannotis (n = 357) or Nyctimystes dayi (n = 304) at either location. The underlying cause was not conclusively determined.