Introduction. Acute pharyngotonsillitis accounts for a large portion of antibiotic prescriptions in pediatric offces. Our aim was to analyze the antimicrobial prescription habits for acute pharyngotonsillitis in children from hospital emergency departments and primary care pediatric clinics in Asturias (Spain). Methods. Multicenter descriptive study evaluating pediatric patients with a diagnosis of acute pharyngotonsillitis in 5 hospital emergency departments and 80 pediatric primary care clinics. Appropriateness of prescription was established by comparing with reference standards. Results. Five hundred sixty-three children with acute pharyngotonsillitis [49.7% in primary care CI 95% 45.6-53.8%)] were included along 30 nonconsecutive days. Antibiotics were prescribed in 75.5% of cases (95% CI 71.9-79.0%) [78.3% in children under 3 years of age (95% CI 71.8-84.8%)]. Amoxicillin was the antibiotic most frequently prescribed [39.1% (95% CI 34.4-43.7%)]. Signifcant differences in the frequency or antibiotic prescription were found between primary care and hospital emergency departments (70% vs. 80.9%, p= 0.003). The treatment prescribed was considered frst choice in 43.3% (95% CI 38.6-48.0%) and inappropriate in 56.0% (95% CI 51.3-60.7%). Conclusions. Although in most cases pediatric acute pharyngotonsillitis is viral in origin, three out of four are treated with antibiotics. Treatment was inappropriate in more than half of the cases in our study.