Delirium remains a significant risk for hospitalized older adults and has been shown to be a persistent risk posthospitalization as well. Dementia is a risk factor for delirium. The prevalence of delirium superimposed on dementia (DSD) ranges from 22% to 89% in hospitalized and community-dwelling individuals 65 and older. Individuals with DSD have been found to have accelerated decline in cognitive and functional abilities, greater need for institutionalization, greater rehospitalization risk, and increased mortality. The purpose of this article is to define and describe DSD, outline assessment tools for its identification, and provide appropriate nursing interventions.