Pulmonary dysfunction is a common complication of head trauma and spinal cord injury. Abnormal breathing patterns reflect the influence of altered neural integration. Early arterial hypoxemia can result from ventilation-perfusion mismatching, microatelectasis, aspiration, fat embolism, or the development of the adult respiratory distress syndrome. Significant changes in lung volumes, ventilation, and gas exchange can occur in spinal cord injury as a result of the loss of diaphramatic or intercostal muscle function. Recruitment of accessory respiratory muscles plays an important role in stabilizing the rib cage and improving expiratory function. Strength training improves expiratory muscle function in quadriplegics and should be continued indefinitely. Most importantly, survival of patients with CNS injuries improves with meticulous and vigorous pulmonary hygiene. The pulmonary hygiene program should include regular changes in the patient's position, assisted coughing and deep breathing exercises, incentive spirometer, bronchodilators, fiberoptic bronchoscopy when indicated, and frequent monitoring of pulmonary mechanics. Long-term survival of the patient with head trauma or spinal cord injury is correlated to successful weaning from mechanical ventilation. Various forms of mechanical ventilator support can be adopted for the patient's ventilatory needs, and many patients will achieve some degree of freedom from mechanical ventilation. Newer ventilatory assist devices that do not require tracheostomy should be considered.