Traditionally, acute medical care has been insufficient to meet the complex care needs of frail older adults. The purpose of this study was to evaluate the effectiveness of Acute Care for the Elderly (ACE) units at improving hospitalization outcomes for adults older than 65 years of age. A review of the literature was performed, focusing on randomized controlled trials, clinical trials, reviews, and meta-analyses from 1990 to 2008. This review revealed ACE to be associated with positive global outcomes (eg, cost, length of stay, readmission rates, utilization, rehabilitation, cognition, function, patient/staff satisfaction). Furthermore, some studies may point to a decreased incidence of delirium and polypharmacy. Though larger studies with consistent operational definitions and replicative studies are needed, the literature presents compelling evidence that warrants further investigation of ACE as a valuable alternative paradigm of acute geriatric care.