Acute sinusitis is a common problem in children that is often overlooked. The pathophysiology is related to obstruction of the sinus ostia and mucociliary dysfunction. The predominant pathogens include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The diagnosis of acute sinusitis is based on persistent or severe upper respiratory tract symptoms. The routine use of roentgenograms to confirm the diagnosis of uncomplicated sinusitis is not recommended for children 6 years or younger but may be considered for children older than 6 years. Antimicrobial therapy is the cornerstone of management and amoxicillin is the drug of choice for most cases of uncomplicated sinusitis.