Antipsychotic drugs are the primary treatment for symptoms of delirium, but their side effects can be problematic. Treatment of delirium with aripiprazole has yet to be evaluated. The authors report on 14 patients with delirium treated with aripiprazole. Twelve patients had a >or=50% reduction in Delirium Rating Scale, Revised-98 scores, and 13 showed improvement on Clinical Global Impression scale scores. There was a low rate of adverse side effects. Aripiprazole may be an appropriate first-line agent for the treatment of delirium because of its minimal effect on QTc interval, weight, lipids, and glucose levels. Controlled comparison studies should be performed to confirm this impression.