Objectives: The WHO anatomical therapeutic chemical (ATC)/defined daily dose (DDD) methodology is a standardized method of comparing antimicrobial use. The ATC/DDD is defined as the average maintenance daily dose of a drug used in a 70 kg adult, ignoring the considerable differences in body weight of neonates and children. The aim of this study was to develop a new standardized way of comparing rates of antimicrobial prescribing between European childrens hospitals. Methods: This pilot study at four European childrens hospitals (in the UK, Greece and Italy) collected data including demographics, antibiotic use, dosing and indication in children and neonates over a 14 day period. Results: A total of 1217 antibiotic prescriptions were issued with 47 different antibiotics used. Approximately half of all children and a third of all neonates received antibiotics, with wide variation between centres in the type and dose of antibiotic used. We propose a new pragmatic three-step algorithm. The first step includes a simple comparison of the proportion of hospitalized children on antibiotics by weight bands and the number of antimicrobials that account for 90 of total DDD drug usage (DU90). The second step is a comparison of the dosing used (mg/kg/day). The third step is to compare overall drug exposure using DDD/100 bed days for standardized weight bands between centres. Conclusions: This novel method has the potential to be a useful tool to provide antibiotic use comparator data and requires validation in a large prospective point prevalence study.