Aim: To assess in infants the number of illness episodes treated with antibiotics and prescription rates in five European countries. Methods: This study was embedded in a multicenter nutritional intervention study and was conducted in five European countries. Infants were followed until 1 year of age. Illness episodes and prescriptions of systemic antibiotics were recorded by the parents. Results: Illness episodes were caused by upper respiratory tract infections (URTIs) in 5564% and by otitis media (OM) in 26.8%. URTIs were statistically significant and more frequently treated with antibiotics in Italy (18.8%), and less frequently in Switzerland (1.4%). OM was statistically significant and less frequently treated with antibiotics in the Netherlands (55%) when compared to Italy (82%). The antibiotic prescription rate varied between countries, ranging from 0.2 to 1.3 prescriptions per infant per year. Conclusions: As the frequency of illness episodes did not differ between countries, other factors, such as physicians attitude, parental pressure or other socio-economic determinants, most likely play a role in antibiotic prescribing habits in the first year of life.