An open, comparative multicenter study was performed to evaluate the efficacy and safety of azithromycin (10 mg/kg) given once daily for three days in comparison with cefaclor (30 mg/kg) divided into three daily doses and given for a period of ten days. One hundred and twenty-two children aged 1-12 years with clinical symptoms of group A β-hemolytic Streptococcal tonsillopharyngitis and a positive throat culture were randomly allocated to the treatment groups. Overall, the clinical success (cure or improvement) of both regimens was identical in the evaluable patients (86.3%, 44 of 51 patients in either treatment group). In contrast, bacterial eradication after completion of treatment was lower with azithromycin than with cefaclor. Possible reasons for this discrepancy between clinical success and eradication rates could be antibiotic resistance, pre-disease carriage or insufficient dosage. Both agents were well tolerated; only mild or moderate side effects most frequently involving the gastrointestinal tract, were recorded in either therapy group.