In contrast to other clinical outcomes, long-term cognitive function in critical care survivors has not been deeply studied. In this narrative review, we summarize the existing literature on the prevalence, mechanisms, risk factors, and prediction of cognitive impairment after surviving critical illness. Depending on the exact clinical subgroup, up to 100% of critical care survivors may suffer some degree of long-term cognitive impairment at hospital discharge; in approximately 50%, decrements in cognitive function will persist years later. Although the mechanisms of acquiring this impairment are poorly understood, several risk factors have been identified. Unfortunately, no easy means of predicting long-term cognitive impairment exists. Despite this barrier, research is ongoing to test possible treatments for cognitive impairment. In particular, the potential role of exercise on cognitive recovery is an exciting area of exploration. Opportunities exist to incorporate physical and cognitive rehabilitation strategies across a spectrum of environments (in the ICU, on the hospital ward, and at home, posthospital discharge).