&NA;We present an unusual case of pneumocephalus secondary to a tension pneumothorax associated with fracture of the thoracic spine. Air from a pneumothorax entered the thoracic intraspinal compartment and the intracranial cavity through a comminuted fracture of the spine. The pneumocephalus and the pneumothorax resolved after aspiration of the intrathoracic air via an intercostal catheter. Diagnosis, therapeutic modalities, and potential complications of a pneumocephalus and of a communication between the thoracic cavity and the spinal dural space are discussed. (Neurosurgery19:120‐122, 1986)