In this study, we evaluated antibiotic utilisation pattern at two paediatric clinics in different European (transitional) countries: Croatia (Rijeka) and Russia (Smolensk). Antibiotic utilisation during the year 2000 was observed using the ATC/defined daily doses (DDD) methodology (ATC code-J01). Drug-usage data was expressed in numbers of DDD/100 bed-days and the DU90% profile. In Rijeka, 35 different systemic antibiotics were used and in Smolensk 22. The overall consumption of antibiotic drugs in Rijeka was more than three times higher than in Smolensk (28.96 vs 8.3 DDD/100 bed-days). The top five antibiotic drugs used in Smolensk were amoxicillin, mydecamicin, ampicilin, doxycylin, gentamicin; and in Rijeka cefuroxime axetil, ceftriaxone, azytromycin, ceftibuten and amoxicillin. Differences in antibiotic prescribing patterns are greater than expected. The pattern of antibiotic utilisation in both countries implies that regional control measures and guidelines for antibiotic use in children should be urgently established.