A 57-year-old man had abnormal hepatic function identified in April 1994. In October 1994, chronic hepatitis C was diagnosed. Based on the findings of a liver biopsy, administration of recombinant interferon (rIFN)-alpha2b was begun. In the 16th week of treatment, the patient experienced headache and fever and developed a markedly decreased, platelet count and hemolytic anemia. He was admitted on May 19, 1995 and thrombotic thrombocytopenic purpura (TTP) was diagnosed. He died on the 3rd hospital day. The causes of TTP have yet to be elucidated, but in this patient the occurrence of TTP appeared to be related to the IFN treatment for chronic hepatitis C.