The ethmoid sinuses play a key role in the health or disease of the entire paranasal sinus complex. Multiple underlying inflammatory processes may easily obstruct the narrow ostia of each ethmoid air cell, leading to infection. By virtue of its unique anatomic position and relationship to the ostiomeatal complex, the ethmoid labyrinth becomes the key to treatment of acute and chronic sinusitis. Surgical intervention for sinus disorders in children has grown in popularity. This article reviews the anatomy and pathophysiology of ethmoid sinusitis and discusses the role of surgery for these disorders.