Six cases of thymic carcinoma (mean age 48.5 years old, one male and 5 females) were treated in our hospital from September 1990 to September 1998. The histological subtypes of thymic carcinoma were squamous cell in 4, undifferentiated in one, and small cell in one. All cases underwent midsternal thoracotomy, 4 had total resection of the tumor and 2 had exploratory thoracotomy due to tumor invasion of the aorta and the main pulmonary artery. Within 2 years after operation, 2 cases without radiation therapy were died of the carcinoma and one case was died of asthma. However, two cases of squamous cell carcinoma have been alive and disease free for 3 and 5 years since the operation followed by mediastinal irradiation. We think that radiation therapy is very effective to control the disease because one of them underwent only exploratory operation prior to irradiation. Another one case who survives 5 years after total resection of the tumor following irradiation revealed swelling of numerous mediastinal lymph nodes, pathologically consisted of non-caseating epithelioid cell granulomas without metastasis of carcinoma, at the time of operation. These lymph nodes were diagnosed as "sarcoid-like reaction" because there was no clinical evidence of generalized sarcoidosis. The "sarcoid-like reaction" may contribute to the 5-year survival of the patient because it is thought to be a local immune response against the cancer cells. A remaining patient, alive 6 months after total resection of the thymic small cell carcinoma following irradiation, received preoperatively three cycles of the intra-arterial administration using CBDCA via bilateral internal mammary arteries. This induction chemotherapy had no response of the tumor size, but it was considered to have a possibility of reducing the size of thymic carcinoma by the use of other agents (CDDP, VDS etc.) because the tumor was fed mainly by the highly developed internal mammary arteries.