The evaluation of dyspnea in the Emergency Department (ED) is a critical step in the diagnostic procedure, especially when cardiopulmonary disease is suspected. Because dyspnea is a symptom in which many different afferent mechanisms are involved, a large number of underlying causes must be considered, alone or in combination. Qualitative and quantitative aspects of difficult or laboured breathing may vary extremely between patients. Therefore, especially under time pressure in emergency situations, it is important to consider a very broad differential diagnosis, and at the same time use a standardized protocol or diagnostic algorithms for the initial work-up.In this article, a standardized work-up published by family practitioners is compared to a standardized work-up proposed by our ED. While practitioners may safely use a multi-step algorithmic approach, it is important in the ED to consider all possible serious underlying conditions at the same time. Over 90 % of all emergency situations are accounted for by only 7 different disease groups. Therefore, all of these must be considered simultaneously in a protocol that is useful for emergency physicians.