Acute respiratory tract infections (ARTIs) are the main reason for antibiotic prescription in children. In 2005, the French Drug Agency published guidelines to minimise inappropriate use of antibiotics for ARTI. The purpose of this study was to assess the impact of implementing these guidelines in a paediatric emergency department. We retrospectively analysed data collected prospectively in a French paediatric emergency department from November 2005 (date of guideline implementation) to October 2009. For each child diagnosed with ARTI, we collected age, diagnosis, and prescribed antibiotics. We computed antibiotic prescription rates in the study population. During the study period, 53,055 children were diagnosed with ARTI and 59% of the 22,198 antibiotic prescriptions given at discharge were related to ARTI. The proportion of ARTI patients given antibiotic prescriptions fell from 32.1% during the first year to 21% in year 4 (p<10(-4), Cochran-Armitage test). Amoxicillin-clavulanic acid and amoxicillin accounted for 50% and 34% of antibiotic prescriptions for ARTI, respectively. French antibiotic guidelines led to significant decreases in antibiotic prescription for ARTI in our paediatric emergency department.