OBJECTIVES: To determine the factors associated with paediatric inappropriate use (IU) of the accident and emergency department (A&E) METHODS: An observational prospective survey was performed. All the patients 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[i], need for technical examination or orthopaedic treatment, in patient admission, death. 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. Two factors were associated with a decrease of IU: parents’ perception of high severity for child’s illness (Adjusted OR 0.6; 95% IC 0.4-0.8) and having a family doctor (Adjusted OR 0.6; 95% IC 0.4-0.9). Two other factors were associated with an increase of IU: children age less than 2 years (Adjusted OR 1.8; 95% IC 1.5-2.2) and night or week-end use of A&E (Adjusted OR 1.4; 95% IC 1.1-1.7). After adjustment, the insurance status has no more impact on the appropriateness of A&E use. 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.