We report a reappraisal of patient NT who became severely amnesic after a right temporal lobectomy for intractable epilepsy (DINSDALE et al., Neuropsychologia 1, 287, 1964 [6]). Histological examination, albeit incomplete, indicated that there was no abnormality in the resected temporal lobe. At autopsy a sclerotic lesion of the unoperated left hippocampal formation was found. This case is therefore not an exception to the general rule that a severe and global amnesic state is only observed with bilateral lesions. Her performance on a wide range of memory tests is shown to be indistinguishable from patients with an amnesic syndrome due to Korsakoff's psychosis.