A total of 49 children (20 females, 29 males; age range, 6 months-12 years) with upper respiratory tract infections (otitis media, sinusitis, pharyngitis and/or tonsillitis) were treated orally with 25 mg/kg.day sultamicillin suspension in two equal doses for an average of 9.2 days. There was bacteriological evidence of sultamicillin-sensitive pathogens in 44 patients prior to treatment. On completion of treatment, 42 (85.7%) patients were rated as clinically cured and there was improvement in the remaining seven (14.2%) patients. Pathogens were totally eradicated in 32/44 (73.7%) cases but were still present in two (4.5%) and in 10 cases follow-up bacteriological evaluation was not possible. Tolerability of sultamicillin was good and only three possible or probable treatment-related adverse events were recorded.