Purpose To evaluate the drug prescription pattern in outpatient children. Methods A systematic literature search was performed in MEDLINE and EMBASE to identify studies published between 1994 and 2008 evaluating drug prescriptions to outpatient children. Results A total of 128 drug utilisation studies were identified, 107 of which were focused on a specific drug class, in particular psychotropic drugs (49 studies) and antibiotics (32 studies). The 21 studies that evaluated all drug prescriptions involved 21 countries, mainly from Europe (13 studies). Large differences were found between studies concerning data source, sample size and age range. A prevalence ranging from 51% in Denmark to 70% in Greenland and a prescription rate (number of drugs per children) ranging from 0.8 in Norway to 3.2 in the United States were reported in the 11 studies that monitored the overall paediatric population. The prevalence rate was higher in preschoolers, with a peak between 72 and 90%, and decreased in children >6 years. Antibiotics were the most prescribed drugs (20-33% of the prescriptions) followed by antiasthmatics (10-25%). According to the results of four studies comparable in terms of data source and children's age, the overall prevalence estimate was 60%. Conclusion A large heterogeneity was found between studies, making a comparative evaluation often difficult or incomplete. The epidemiological evaluation of drug use in children should therefore be improved, in particular in terms of methodological quality of studies, and prospective multinational collaborative studies aimed at collecting valid and comparable data should be performed to improve the rational use of drugs.