Résumé : Objective: To determine the factors associated with paediatric inappropriate use (IU) of the accident and emergency department (A&E). Method: An observational prospective survey was performed. All the patients (< 16 years) attending A&E in 12 Belgian hospitals during 2 weeks in 2010 were included. The use of A&E was considered appropriate if, at least, one of the following criteria was met: child referred by a doctor or the police, brought by ambulance, need for a short stay, need for technical examination or orthopaedic treatment, in patient admission, death. A short stay is A&E attendance which the duration is between 4 and 24 hours. Results: The median age of the 3220 children included was 3.3 years old (0-15.9); 39.3% of the visits were not appropriate according to the definition above. Five determinants were included in a multivariate analyze: age, having a family doctor, night or week-end use of A&E, parents’ perception of severity for child’s illness and insurance status. The multivariate model (table 2), showed that the disadvantage families had not more risk for IU after controlling for other variables. Four factors were associated with an increase of IU: children’s age less than 2 year old, night or week-end attendance, short home-ED distance and, surprisingly, having a family doctor. The parent’s perception of high severity for child’s illness and the localization in Flanders region were associated with a decrease of IU. Conclusions: In a country like Belgium, where it is not compulsory to be registered with a family doctor, the risk of an IU is mainly due to the failure of outpatient care for children <2 years and the use of A&E during night or weekend. Parents’ perception of high severity for child’s health status and having a family doctor were associated with the appropriateness of A&E use.