Characteristically pulmonary edema is bilateral, unless there is an underlying defect or abnormality in the cardiopulmonary system. Unilateral pulmonary edema following general anesthesia is a rare complication in a healthy patient. The etiology of unilateral pulmonary edema include, the re-expansion of a collapsed lung, unilateral pulmonary veno-occulusive disease, pulmonary contusion, compression of pulmonary vasculatures, cerebral autonomic dysfunction, bronchial obstruction and severe ischemic left ventricular dysfunction. We describe a 52-yr-old patient who developed acute unilateral pulmonary edema after a total hip replacement athroplasty in the lateral decubitus position. The patient recovered following 16 hours of intensive treatment involving fluid restriction, diuretics, sedation, and continuous positive airway pressure ventilation.