The development of an acute pleural effusion during the immediate postoperative period after abdominal or pelvic surgery is not uncommon. In symptomatic patients, pleural effusions often are thought to result from a complication of pulmonary embolism or parapneumonic effusion. We present a patient in whom an acute unilateral hepatic hydrothorax developed after elective total abdominal hysterectomy. Pleural effusion continued to reaccumulate for several days. After extensive efforts failed to reveal the cause of effusion, intraperitoneal radioisotope study confirmed a peritoneopleural communication associated with unsuspected and asymptomatic hepatitis C-induced cirrhosis of the liver with portal hypertension.