A patient with central pontine myelinolysis (CPM) underwent neurological and mental status examination, as well as neuropsychological testing, during the acute stage of the disease. After correction of the hyponatremia, a gross change in his neuropsychiatric status was observed. The patient underwent extensive neurological, psychiatric, and neuropsychological testing during the acute phase of the disease and at follow-up 4 months later. All major neurological and neuropsychiatric symptoms present at onset were fully reversible. Neuropsychological examination revealed deficits in the domains of attention and concentration, short-term memory and memory consolidation, visual motor and fine motor speeds, and learning ability. Although improved, neuropsychological testing still revealed remarkable deficits at follow-up. We conclude that neuropsychological deficits can accompany CPM, and that these deficits do not necessarily diminish simultaneously with the radiological or clinical neurological findings but may persist for a longer period of time, or even become permanent. In his recovery the patient started to manifest new neurological symptoms consisting of a mild resting tremor of both hands and slow choreoathetotic movements of the trunk and the head, which we considered to be late neurological sequelae of CPM. The significance of CPM in the differential diagnosis of acute behavioral changes after correction of hyponatremia is stressed, even if correction is achieved slowly and carefully.