Eight patients with alcoholic Korsakoff's syndrome were compared to age-matched groups of normal controls and nonamnesic chronic alcoholic patients using magnetic resonance imaging (MRI). Quantitative image-analytic techniques were used to estimate volumes of ventricular and cortical cerebrospinal fluid (CSF), as well as cortical and subcortical grey matter structures. For the nonamnesic alcoholics, these volume analyses revealed large CSF increases with some circumscribed decreases in grey-matter volumes. In contrast, alcoholic Korsakoff patients showed widespread reductions in grey matter volumes in addition to CSF increases, with greatest reductions observed in diencephalic structures. The volume losses that best differentiated the Korsakoff patients from the alcoholic controls included losses in anterior portions of the diencephalon, mesial temporal lobe structures, and the orbitofrontal cortices. These findings suggest that damage to structures other than the mesial thalamic nuclei, such as the hypothalamus and hippocampus, may contribute to the Korsakoff patients' amnesic symptoms.