Sinusitis is a common disease in children. Acute, uncomplicated rhinosinusitis following viral upper respiratory infection usually resolves without antibiotic therapy, with a minority of cases persisting as chronic rhinosinusitis. In children with chronic rhinosinusitis refractory to medical therapy or with overlying medical illness such as cystic fibrosis or ciliary dysmotility, endoscopic sinus surgery has become a mainstay of treatment. Other modalities, including sinus aspiration and irrigation, adenoidectomy, and reflux treatment, may be used in selected patients in lieu of endoscopic sinus surgery. The generally favorable course of chronic rhinosinusitis with medical management makes endoscopic sinus surgery unnecessary for the majority of patients with this disease.