Upper respiratory tract infections are the most common source of antibiotic prescriptions. Acute pharyngitis is caused mainly by viruses, viral cases can be distinguished from acute streptococcal pharyngitis using Centor clinical epidemiological criteria, by rapid antigen tests or throat culture. Treatment of choice for streptococcal infection is penicillin V given in two daily doses. In children, acute otitis media (AOM) is the infection for which antibiotics are most often prescribed. Predominant causative pathogens include Streptococcus pneumoniae, Haemophilus influenzae non-type b and Moraxella catarrhalis. Diagnosis is based on history, physical examination and otoscopic exam. Antibiotic treatment should be initiated promptly in all children<2 years of age, and in older children presenting bilateral AOM, otorrhoea, co-morbidities or severe illness. In Argentina, amoxicillin is the drug of choice given the low penicillin resistance rates for S. pneumoniae. In children who fail amoxicillin therapy, amoxicillin/clavulanate provides better coverage against beta-lactamase producing H. influenzae and M. catarrhalis. Rhinosinusitis is caused mainly by viruses, secondary bacterial complication occurs in less than 5% of cases. Diagnosis is based on physical examination and additional studies are not usually required. Acute bacterial sinusitis is caused by the same pathogens that cause AOM and amoxicillin is the drug of choice.