Immunohistochemical SABC was performed to analyze the expression of ZENK protein in the brain of female concave-eared torrent frogs (Odorrana tomorta) under background noise, the voice of male concave-eared torrent frogs and the voice of the male large odorous frog (O. graminea). The results showed that there were no ZENK protein-positive cells in the telencephalon, diencephalon and cerebellum of the female concave-eared torrent frogs (Fig. 2, 4) stimulated by aforementioned three voices. The cells in optic tectum, interpeduncular nucleus rostral portion, nucleus profundus mesencephali, tegmentum, torus semicircularis of the mesencephalon and the cells in solit tract nucleus, raphe nuclei, reticular nuclei, reticular formation, superior olivary nucleus of the medulla oblongata in female concave-eared torrent frogs showed positive reaction under the stimulation by the voice of male concave-eared torrent frogs (Fig. 3, 5), while the numbers of positive cells in aforementioned areas of the brain were markedly reduced under the stimulation from the voice of the large odorous frog. Part of the ZENK protein-positive cells were located in the torus semicircularis, tegmentum of mesencephalon and the superior olive nucleus of medulla oblongata, which were related to the processing of auditory information in amphibians. It can be inferred that ZENK protein is closely related to the processing of auditory information in female concave-eared torrent frogs.