Numerous studies over the past decade have reported an acute change in cognitive status in adult patients after major surgery. Most evidence suggests that these early cognitive changes are transitory and do not persist in the long term. However, the prognostic significance of POCD remains a hotly debated topic, especially in light of recent data showing that patients with early POCD were at higher risk of mortality after discharge. Furthermore, whether patients with early POCD actually have preexisting mild cognitive impairment and experience a steeper downward cognitive trajectory independent of the effect of anesthesia and surgery is another question that warrants further investigation. We anticipate that future studies will elucidate better the pathophysiology of POCD through the use of large sample sizes and longitudinally collected patient data in both the early and late postoperative period. We also advocate for a theoretically derived and empirically tested model which describes the causes and outcomes of POCD. Such a model must be established in order to truly standardize the neurocognitive test battery and timing of administration in the study of POCD.