OBJECTIVE. The purpose of this article is to acquaint the reader with the clinical and imaging features of the silent sinus syndrome, which is relatively unknown. Discussion of the presentation, treatment, and theory regarding pathogenesis of the syndrome follows. CONCLUSION. The silent sinus syndrome consists of painless facial asymmetry and enophthalmos caused by chronic maxillary sinus atelectasis. Although the diagnosis is usually suspected clinically, it is confirmed radiologically by characteristic imaging features that include maxillary sinus outlet obstruction, sinus opacification, and sinus volume loss caused by inward retraction of the sinus walls.