The work was done on 24 rats. Positive conditioned reflexes to sound and light were elaborated; differentiation to interrupted sound and light, conditioned switching over of various food and defense reflexes to sound and light were also formed. Once these conditioned reflexes are consolidated the cortex of the temporal lobes is removed. Changes in the conditioned-reflex activity after the operation demonstrated that in rats the auditory function is localized in the temporal cortex, and this not only in solution of a simple task, but also of a differential one, and of a complicated task involving switching over of conditioned reflexes. The available data show that the more complex the task — the later and with the greater difficulty the preoperative reflex level is restored. These data also demonstrate the advantages of the conditioned-reflex methods over the labyrinth one for solving the problem of functional localization in the large hemispheres. The data obtained confirm the correctness of I. P. Pavlov''s assumptions on the presence of the functional localizations in the cortex of rat cerebrum, and show the erroneousness of Lashley''s theory of equipotentialism.