Visits by older adults compose 12-21% of all emergency department (ED) encounters [1]. Furthermore, studies showed a progressive increase in the number of ED attendances and emergency admissions hospital of older patients in the last decade. Between 30 and 50% of all ED visits by older patients result in a hospital admission. Lastly when admitted, older emergency patients are more likely to require an ICU (ntensive care unit bed [2]. Acute respiratory failure (ARF) is a common complaint of elderly patients in ED, and the key clinical presentation of cardiac lcongestive heart failure (CHF)] and respiratory disorders [3]. This article will summarise the age-related structural changes of the respiratory system and their consequences in clinical practice. It will also overview the causes, difficulties in diagnosis, treatment and prognosis of ARF in elderly patients. Scarches were conducted in MEDLINE for published studies in the English language between January 1980 and August 2007, using acute dyspnea', acute respiratory failure', "heart failure Pneumonia, pulmonary embolism (PE)'keywords and selecting articles concerning patients aged 65 or over.