Abstract 1. 1. The predominance of individual catecholamines in the adrenal glands of frogs from south-east Australia is associated with the family to which the species belongs. 2. 2. Adrenaline predominated in all 8 species representing the Hylidae, and noradrenaline in 6 of 7 leptodactylid species. 3. 3. Adrenal catecholamines are probably conservative in the evolutionary sense and provide an index of phylogenetic relationships.