Old age and organic brain disorder are major risk factors for delirium in the elderly. The localization of the brain damage in dementia may be of importance for this risk. The aim of the present study was to investigate the rate of delirium in patients with different regional brain syndromes. Included in the study were 194 demented patients. The occurrence and intensity of four regional brain syndromes were estimated: parietal lobe syndrome, frontal lobe syndrome, subcortical syndrome and global brain syndrome. The analyses showed that the rate of delirium was significantly higher when a global brain syndrome was predominant than when any one of the other syndromes predominated.