The aim of the study was to analyze five patients with Alzheimer's disease in whom the degree of dementia assessed by cognitive and functional tests was at variance with the behavior in the dental setting and to relate these factors to the outcome of the graphic test. Possible reasons for the differences were discussed. The subjects were diagnosed as having Alzheimer's dementia on the basis of the DSM-III-R. Their cognitive and functional impairments were assessed with the Mini-Mental State Examination test and Katz's index of activities of daily living. Behavior in the dental office was registered in a structured form. The graphic function was assessed as Human Figure Drawing. Besides the stage of dementia, the patient's personality, social and medical background, and memories of previous dental care influence the demented patient's behavior in the dental office. To provide secure conditions for treating demented patients, the dentist must be able to interpret the patient's unique personality in the context of the dental situation.