A total of 384 children with group A beta-haemolytic streptococcal (GABHS) pharyngitis were randomized to receive either 40 mg/kg/day of cefaclor in two doses for 5 days (192 patients), or 40 mg/kg/day of amoxycillin in three doses for 10 days (192 patients). The signs and symptoms of pharyngitis were recorded and throat cultures were obtained at presentation and on days 6-7, 11-15, 16-20 and 28-35. Patient compliance was significantly higher in the children treated with cefaclor (100 vs. 95.1%; P = 0.003). At the end of follow-up, the percentage of clinical success was 91.4% for cefaclor and 91.9% for amoxycillin (P = 0.974); bacteriological success was obtained in 85.7 and 89.6% children (P = 0.348), respectively. Both treatments were well-tolerated with adverse event rates of 8.3% in the cefaclor group and 9.4% in the amoxcillin group (P = 0.857). Our study shows that five days' treatment with cefaclor is as effective and safe as the conventional 10-day course of amoxycillin in the treatment of GABHS pharyngitis, but compliance seems to be significantly greater.