Frailty is an aging-related, multisystem clinical state characterized by loss of physiological reserves and diminished capacity to withstand exposure to stressors. Frailty increases the risk of serious adverse outcomes, compared with that of nonfrail people of the same age. Adverse outcomes can be severe and may include procedural complications, delirium, significant functional decline and disability, prolonged hospital length of stay, extended recovery periods, and death. As older adults make up a continually growing proportion of hospitalized patients, critical care nurses need to understand how to recognize frailty and be familiar with related clinical practice implications. Such knowledge underpins effective organization and delivery of care strategies aimed at minimizing harm and maximizing positive outcomes for frail older adults. Drawing from recent literature, this article explores frailty and critical illness by discussing 2 dominant models of the concept. Using a clinical case study, links between frailty and critical care nursing practices are highlighted and clinical considerations are explored.