Pneumomediastinum (PM) secondary to an isolated orbital blow-out fracture is a rare but potentially severe and life-threatening complication. Fortunately, airway obstruction, pneumothorax, pneumopericardium, and mediastinitis are rare complications of PM. Blowing the nose after a maxillofacial trauma increases pressure in the paranasal sinuses, which may lead to emphysema through a breach of the lining mucosa to the surrounding soft tissues in the head, neck, and, on occasions, to the mediastinum. We report here the rare case of a patient with PM after isolated orbital fracture. Only 3 similar cases have been previously reported in the literature.