The efficacy and safety of a 3-day course of azithromycin oral suspension (10 mg/kg of body weight once daily) were compared with those of penicillin V (50,000 U/kg/day in two divided doses) in children aged 3 to 12 years for the treatment of symptomatic pharyngitis caused by the group A beta-hemolytic streptococcus (GABHS). For the 154 evaluable patients, the original infecting strain of GABHS was eliminated at the end of follow-up (34 to 36 days after treatment started) from 67 (85.8%) of 78 penicillin-treated patients and 41 (53.9%) of 76 azithromycin-treated patients (P < 0.0001). Overall clinical success was achieved in 71 (91.0%) of 78 penicillin V-treated patients and 57 (75.0%) of 76 azithromycin-treated patients (P < 0.05). Potential drug-related adverse events were reported for 5.5 and 8.6% of the penicillin V- and azithromycin-treated patients, respectively (P = 0.6). In the present study, a once-daily (10 mg/kg), 3-day oral regimen of azithromycin was as safe as a 10-day course of penicillin but did not represent an effective alternative to penicillin for the treatment of GABHS pharyngitis, even for those children with azithromycin-susceptible strains.