We report a case of temporary pancytopenia with hypoplastic bone marrow after an operation for hilar bile duct carcinoma. A 51-year-old man was admitted to the hospital because of jaundice. Close examinations revealed hilar bile duct carcinoma. He underwent a left hepatectomy, a bile duct resection, and an intraoperative radiation therapy (20Gy). Moreover, he received remote after loading system (24Gy) because of positive surgical margin. On 54th day after the operation, he complained of general fatigue and laboratory examinations revealed pancytopenia and renal failure. Thereafter the number of platelet cells decreased to 12, 000 and white blood cells to 500. Biopsy of the bone marrow revealed hypoplastic change. Steroid pulse and symptomatic therapies were effective and he recovered 64 days after the operation. The cause of suppression of the bone marrow was still abscure. He had no fever and abnormalities on examinations for coagulants. It is necessary to start treatments for bone marrow suppression as soon as possible. And it is thought that there are some cases of unknown orgin for which steroid pulse therapy is useful in addition to medication with glanulocyte stimulating factor or platelet transfusion.