The authors report a clinico-pathological study dealing with the limbic nuclei of the thalamus in 11 cases of Korsakoff syndrome of alcoholic aetiology. There is no parallelism between the involvement of the latero-dorsal nucleus (L.D.), the medio-dorsal nucleus, the pulvinar and the importance of the retrograde amnesia. The mamillary bodies are always affected. The latero-dorsal nucleus was modified in 9 cases out of 11, the medio-dorsal in 7 cases and the pulvinar in 6 cases. In contrast, the anterior nucleus is normal. The frequency of the involvement of the L.D. is an argument to relate this nucleus with the limbic system. But the lesion of this nucleus is inconstant whereas that of the mamillary bodies is always observed.