The auditory sensitivity of 17 species of Australian anurans was measured by recording responses of groups of midbrain auditory neurones to sound stimuli of different frequencies. In 14 species there are two peaks of maximal auditory sensitivity and in three species there are three peaks. In all species the sensitivity peak which occurred at the higher frequency corresponded to the frequency of the mating call. There is a significant correlation between the auditory threshold at this higher sensitivity peak and both head width and tympanum width.