We present a case of a woman who received a left single-injection supraclavicular brachial plexus block for analgesia to facilitate upper extremity orthopaedic surgery. Before tracheal extubation she desaturated, was noted to have a low tidal volume and reduced left-sided air entry on auscultation of the chest. A chest x-ray taken 1 h following tracheal extubation revealed elevation of the left hemidiaphragm and a rightward shift of the trachea and mediastinal structures, with no evidence of pneumothorax. Findings were in-keeping with phrenic nerve palsy complicating the brachial plexus block performed. The patient was asymptomatic and discharged home the next day following repeat chest x-rays. We believe this is the first report of tracheal deviation contralateral to the side of an elevated hemidiaphragm secondary to phrenic nerve palsy from a brachial plexus block.