OBJECTIVE To establish the relationship between cognition, behavior, function, and clinical characteristics on the one hand, and the presence of primitive reflexes (PR) (pout, snout, palmomental and grasp) in patients with Alzheimer's disease (AD). METHODS Cross-sectional survey. METHODS Secondary care geriatric practice specializing in the assessment of cognitive impairment. METHODS 136 consecutive patients presenting with AD. METHODS PR were assessed in standardized fashion by a single clinician. Cognitive function was measured using the Standardized Mini-Mental Status Examination, activities of daily living (ADL) and instrumental activities of daily living (IADL) were measured using the Lawton scale, and behavior was measured using the Behavioural Problem Checklist. RESULTS There was no difference in age or duration of dementia in those with and without PR, nor was there any difference in cognitive function. Despite this, patients with PR showed a greater degree of functional limitation and dysfunctional behavior. There was also a higher incidence of rigidity, gait abnormalities, and apraxia in patients with PR. CONCLUSIONS Patients with primitive reflexes had more severe impairment in ADL function and dysfunctional behavior for an equal level of cognitive function.