Studies have been made on the reactions of 34 neurones from the accessory olfactory bulb of the frog Rana temporaria to stimulation of the receptors in the vomeronasal organ by amino acids (L-alanine, L-aspartic acid, L-valine, L-glytamic acid, glycine, L-proline, L-serine), carboxylic acids (acetic, glutaric, isovaleric, propionic and succinic acids) at a concentration 10(-4) M, as well as by "rinsing" the frog's skin. The general pattern of the background and evoked activities in the neurones of the accessory and main olfactory bulbs is similar. Neurones of the accessory bulb exhibited selective responses to all the amino acids at a concentration 10(-4) M, in which they are effective for stimulation the olfactory receptors of bony fishes. This finding indicates the adequate nature of the stimulation used for receptors of the vomeronasal organ, as well as underlies functional similarity of these receptors in the frog with the olfactory receptors of fishes.