Recognizing delirium and its impact on older patients and their caregivers is an important aspect of oncology nursing. Delirium is the most common complication of hospital admissions for older adults and is associated with a significant amount of morbidity and mortality, prolonged hospital stays, functional decline, and decreased quality of life. Oncology nurses caring for older patients with cancer have the opportunity to recognize the onset of delirium, provide ongoing patient assessment and monitoring, and implement pharmacologic and nonpharmacologic interventions.