The silent sinus syndrome consists of painless facial asymmetry characterized by unilateral enophthalmos. Reabsorbed bone with displacement of the orbital floor is a constant finding. It is secondary to chronic maxillary sinus atelectasis. The onset of symptoms is usually slightly progressive but can be brisk due to sudden collapse of the orbital thin bony floor. The diagnosis is suggested by clinical findings including endonasal endoscopic examination and confirmed on the basis of computed tomography and magnetic resonance imaging. The restitution treatment of the silent sinus syndrome involves functional endoscopic sinus surgery and plastic reconstruction of the floor of the orbit via transconjunctival approach; an additional vestibular incision may be necessary to treat the malar region. Four cases of this rare and therefore relatively unknown disease are fully discussed.