A 53-year-old man with a history of blood transfusion at the age of 20 was admitted to our hospital because of liver dysfunction. He had bronchial asthma when he was 18 years old, which naturally resolved within 2 years. However, his bronchial asthma recurred at the age of 45 and was treated with oral theophylline. He was diagnosed as having chronic hepatitis C based on the histological and clinical findings, and then interferon (IFN) therapy was administered. The frequency of bronchial asthma attack was gradually decreasing after IFN therapy with marked improvement of hypereosinophilia. He achieved sustained viral response (SVR) and his bronchial asthma did not worsen even after the cessation of IFN. Hepatitis C virus (HCV) infection and IFN therapy were considered in the remission of asthma in this case. HCV infection could be the cause of bronchial asthma, especially in patients with late appearance of asthma. A 53-year-old man with a history of blood transfusion at the age of 20 was admitted to our hospital because of liver dysfunction. He had bronchial asthma when he was 18 years old, which naturally resolved within 2 years. However, his bronchial asthma recurred at the age of 45 and was treated with oral theophylline. He was diagnosed as having chronic hepatitis C based on the histological and clinical findings, and then interferon (IFN) therapy was administered. The frequency of bronchial asthma attack was gradually decreased after IFN therapy with marked improvement of hypereosinophilia. He has sustained viral response (SVR) and his bronchial asthma did not worsen even after the cessation of IFN. Hepatitis C virus (HCV) infection and IFN therapy were considered in the remission of asthma in this case HCV infection could be the cause of bronchial asthma, especially in patients with late appearance of asthma.