We report two cases of Jehovah's Witness patients who had massive bleeding after surgery. The first case was a 37-year-old woman who underwent an emergency cesarean section; the other was a 48-year-old man with chronic anemia who underwent removal of a large mass. After the operation, their Hb levels were nearly 3.1 g/dl. They were treated with blood conserving methods, divided into 3 periods (pre, post and operative). Both patients completely recovered uneventfully and were discharged on the 19th and 21st postoperative day.