Dichotic listening test was administered to a right-handed patient with section of the splenium and probably the posterior end of the truncus of the corpus callosum owing to a germinoma. The patient showed the supression of left ear stimuli both on the divided attention and on the focused attention. The results indicated that the splenium plus the posterior end of the truncus or the splenium is crucial in the interhemispheric transfer of speech inputs from the right hemisphere to the left.