Postoperative delirium (POD) is the most common adverse neurologic complication that can occur in patients of any age. Its incidence varies across age groups and is substantially influenced by patient-related risk factors. POD occurs in 17%-61% of major surgical procedures. Several risk factors which contribute to the development of POD include age more than 60 years, pre-existing cognitive dysfunction, presence of comorbidities, sensorial deficits, malnutrition, polypharmacy, impaired physical mobility and frailty. Postoperative delirium has several wide ranging and adverse outcomes that are consistently associated with delirium such as mortality, increased length of hospital stay, and increased hospital costs. A recently devised tool for rapid assessment of delirium is the 4 A's test. It has now been validated for identifying delirium in the surgical population. The proposed prospective observational study will be conducted on 150 patients belonging to ASA Physical Status I-III of either sex, scheduled to undergo non-cardiac surgery under general anaesthesia (GA), requiring at least 24 hours of postoperative inpatient care. This prospective, observational study aims to evaluate the incidence, risk factors and outcomes of postoperative delirium in elderly patients more than 65 years of age undergoing non-cardiac surgery.