Neuropsychologists often recommend that patients with dementia and their caregivers use environmental adaptations to improve everyday functioning. Although these recommendations are intuitive (e.g., reduce clutter), most have never been experimentally tested. This study examined whether and how environmental adaptations improved everyday action in Alzheimer's disease (AD). Forty-six outpatients completed the Naturalistic Action Test (NAT; M. F. Schwartz, L. J. Buxbaum, M. Ferraro, T. Veramonti, & M. Segal, 2003), which requires completion of 3 everyday tasks. The NAT was administered under 2 conditions: standard and user centered. The standard NAT followed the procedures of the manual; object placement was standardized, but objects were not meaningfully arranged on the tabletop. In the user-centered NAT, objects were arranged in the order needed in the task, and a visual cue to monitor performance was placed on the table. These conditions were counterbalanced across participants. The user-centered condition improved performance on all NAT items and reduced commission and omission error rates. However, post hoc examination of commission error types showed improvement of substitution and off-task errors but no difference in anticipation and perseveration errors. Thus, environmental adaptations improved everyday performance in AD by facilitating task accomplishment, object selection, and task-congruent actions.