This chapter discusses evidence-based management of pediatric chronic rhinosinusitis, where various medical conditions predispose individuals to recurrent or chronic sinus infections. Environmental allergies leading to respiratory mucosal inflammation and stasis of upper respiratory secretions are a likely risk factor for sinusitis, where the actual prevalence of recurrent or chronic sinusitis amongst allergic children is unknown. The physical examination is directed at assessing signs of active infection within the nose and sinuses. Nasal endoscopy with a rigid or flexible telescope requires more elaborate equipment than anterior rhinoscopy and is less well tolerated by children. Standard radiographic imaging of the sinuses has a minor role in the evaluation of patients with suspected chronic rhinosinusitis. Oral antibiotics constitute the major antimicrobial therapy for chronic sinusitis. Gastroesophageal reflux (GER) has recently become identified as a contributor to diseases of the upper respiratory tract.