An open multicentre study was conducted in 484 children between the ages of 6 months and 12 years with otitis media to compare the efficacy, the safety and the tolerance of once-daily azithromycin given for three days versus thrice-daily amoxicillin/clavulanic acid (CA) given for ten days. A satisfactory response (cure plus improvement) was noted 10 to 14 days after the start of treatment in 199 of 215 (92.6%) azithromycin-treated children and in 186 of 198 (93.9%) amoxicillin/CA-treated children. The relationship between treatment and clinical response was independent of chronicity of infection and the presence or absence of a perforated eardrum. Improvement in signs and symptoms of otitis media occurred significantly more rapidly in the children treated with azithromycin. Treatment-related or possibly treatment-related adverse events were recorded in 11 of 243 (4.5%) azithromycin-treated patients and in 20 of 240 (8.3%) treated with amoxicillin/CA. No patients in the azithromycin treatment group were withdrawn from treatment, but six amoxicillin/CA patients, including two < 2 years of age, discontinued treatment prematurely because of adverse events; the difference between treatment groups was statistically significant (p = 0.0146). It is concluded that azithromycin given as an oral suspension once daily for three days is as safe and effective as amoxicillin/CA given thrice daily for ten days in the treatment of children with otitis media.