Aggressive behaviour is common in dementia patients and causes a seriour burden for their relatives and caregivers. Lesions in the temporolimbic lobes and prefrontal cortices have been reported to produce pathological aggression both in animals and humans, however, involvement of these structures is not established in dementia patients with aggression. To address this issue we compared the pattern of regional cerebral perfusion in two groups of dementia patients with and without aggression, which were comparable in demographic factors, severety of cognitive impairments, and other behavioral symptoms measured by the Neuropsychiatryc inventory. Patients with aggression revealed significant hypoperfusion in the left anterior temporal cortex as compared to those without aggression. In addition, regional cerebral perfusion in dorso-frontal cortex bilaterally and of the right superior parietal cortex was significantly decreased. These results indicated an association between aggression and disfunction of these cortical regions, irrespective of the disease origin.