Using DSM-III-R criteria, five patients (ages 46 approx. 76 years) were diagosed as having DAA (dementia associated with alcoholism). An investigation was conducted using a ring-type single proton emission tomography system with N-isopropyl-p-(/sup 123/I) iodoamphetamine (IMP) and a magnetic resonance imaging system with a superconductive 2 tesla magnet. IMP uptake was measured 25 approx. 30 minutes after injection. Bilateral IMP uptake reduction was seen in all of the patients. The distribution of the reduced IMP uptake showed in the temporal region of all patients ; the frontal region in four of the patients and the occipital region in two of the patients. The reduction of IMP uptake was irregular, generally mild, and less severe than that of Alzheimer type dementia. The MRI study showed cortical atrophy, especially in the frontal and temporal areas, and also showed enlargement of the lateral and third ventricles. The reduced IMP uptake corresponded to cerebral atrophy and ventricular dilatation on the SE image (TR 3000, TE 60 or 82). These results indicate that the IMP SPECT and MRI studies are useful in examining DAA patients and in the classification of other types of dementia.