Comprehensive geriatric assessment (CGA) may benefit frail or chronically ill patients in the emergency department (ED), but take too much time to be performed routinely in ED. An alternative approach is to use first a screening tool to detect high-risk patients and then perform CGA in these patients only. This systematic review focuses on the use and value of CGA in ED for evaluation of older patients and its influence on adverse outcomes. This approach is compared with an alternative one using existing screening tools, validated in ED, to detect high-risk patients needing subsequent CGA. This review ends by suggesting a short assessment of CGA to be used in ED and ways to improve home discharge management from ED.