Background: Emergency Medical Services (ES) are medical-surgical facilities where extremely ill patients, victims of accidents, intoxications and other urgent clinical situations should be rapidly and efficiently attended. However, a worldwide experience is that a large proportion of patients who require attention in an ES do not qualify as emergencies and they obstruct the possibilities of other patients that should be attended immediately. Aim: To evaluate the medical records in our ES and to assess whether patients understand what is a true emergency and which is the role of an ES. Methods: Patients attended in the ES of Haydarpasa Military Teaching Hospital in 2001-2002 were classified according to their diagnosis. A random sample of patients and relatives were surveyed about why they required medical attention in the ES. Results: 77,134 patients (39,327 female, 51%) were attended. The most common illness diagnosed was upper respiratory tract infection (18,423 patients, 23.9%). The true emergency condition rate in patients presenting to our ES was lower (44%) than the non-emergency condition rate. Conclusions: Improvements in public education are needed to solve this problem. Also, Primary Care facilities should be improved in order to reduce the demand for medical attention in ES by non-urgent patients (Rev Méd Chile 2004; 132: 1085-9)