Evaluation of patients with suspected Alzheimer's disease (AD) often involves clinicians of multiple disciplines working in collaboration to maximize diagnostic accuracy. Accordingly, repeated administrations of some common tests of mental status may occur within a relatively brief time period. The effect of such retesting on subsequent results is largely unknown for many cognitive tasks, despite the possibility that repeated administrations may artificially inflate scores. To assess the potential impact of practice effects on a commonly administered verbal fluency task, animal naming was administered twice within a 1-week period to 111 patients with probable AD and 12 persons without dementia. Non-demended subjects were the only group to demonstrate a small (3 point), but statistically significant practice effect. Regardless of level of cognitive impairment, patients with AD did not show significant practice effects over repeated administrations of animal naming after a relatively brief test-retest interval, suggesting the robust nature of this task in AD.