We present a patient with transient global amnesia (TGA) whose diffusion-weighted imaging (DWI) study showed a high-intensity signal in the left retrosplenium of the corpus callosum. In previous studies, lesions in the retrosplenium caused permanent but not transient global amnesia, called retrosplenial amnesia, by involving the thalamocortical portion of the Papez' circuit. This is the first report indicating that TGA can be associated with acute infarction only in the left retrosplenium of the corpus callosum.