Abstract : Studies about patients’ profile presenting to the emergency department for dyspnea are scarce in Europe, and even more in Belgium. We analyze here a cohort of patients with acute dyspnea in three Belgian centers, as to the epidemiology of this dyspnea, the tests carried out, the diagnoses retained, the treatments administered, the hospitalization and survival rates. The secondary objective is to compare this Belgian cohort with a European population resulting from a large multicenter study. The analysis of 131 patients showed that acute dyspnea in the emergency department corresponds to four main diagnoses (exacerbation of chronic obstructive pulmonary disease, infections of the lower respiratory tract, acute cardiac decompensation and asthma). The age of patients is over 80 years in a quarter of them, the hospitalization rate is 57 % and the mortality is 5 %. Our analysis also reveals that the check of vital parameters may be insufficiently realized, as may the use of non-invasive ventilation. Etiological diagnoses made in the emergency department are confirmed at the end of hospitalization in 75 % of cases. The Belgian population is younger than the European population (62 against 69 years), presents fewer infection of the lower respiratory tract (20 % against 31 %), and is comparable to the European population for the other parameters studied. The article ends with 10 key messages that will enlighten clinicians about the reality of acute dyspnea in emergency rooms in Belgium.