Alzheimer day-care clients received three months of Mon-tessori type activities and three months of routine activities, in a within-subjects design. The effects of the two conditions were compared using changes in clients' scores on 22 cognitive measures. From this, a measure of performance after the Montessori activities, compared to after routine activities (Montessori Benefit Score), was calculated for each subject and a distribution of subject scores was generated. Using a resampling statistic, the mean Montessori Benefit Score was compared to one obtained under a null hypothesis that no difference existed in performance between routine and Montessori conditions. The observed mean Montessori Benefit Score (m = 7.4) fell outside the 95% confidence interval for the means based on the null hypothesis, indicating that Montessori materials benefit the Alzheimer's clients in this study. © 2000 by The Haworth Press, Inc. All rights reserved.