Acute paranasal sinus infection in children is often diagnosed clinically without the need for radiographic confirmation. Most cases have a favorable outcome following appropriate antibiotic therapy. A small percentage of cases where symptoms and signs are persistent or severe will require emergent imaging to rule out complications related to local spread of disease intraorbitally or intracranially. A strong index of suspicion is required in such cases, and cross-sectional imaging evaluation with CT and MRI should include axial and coronal images of the paranasal sinuses and, where appropriate, the orbits and brain (with attention to the cavernous sinus). There is no role for plain radiography in the evaluation of the complications of acute sinusitis in the pediatric patient.