Between January 1977 and March 1991, 86 patients of Stage III and Stage IV breast cancer were treated by intra-arterial infusion chemotherapy (IAIC) in Sapporo Medical College. The 5- and 10-year overall survival rates of Stage III b were: infusion group 53.1% and 53.1%, non infusion group 50.1% and 16.7%, respectively. A significant difference was seen in the 10-year survival rate (p less than 0.05). The 5- and 10-year overall survival rate of Stage III b histologically effective group was 67.3% and non-effective group 31.8%. A significant difference was seen between these two groups (p = 0.0241). A significant difference was seen between n2 positive Stage III b infusion group and non-infusion group in 7-year survival rate (p less than 0.01). The ischemic effect on tumor cells by degeneration changes of the blood vessels was important for the histological effect. Pre-operative angiography helped in the choice of anticancer agents. The sufficient adjuvant chemo-endocrine therapy will assure a good prognosis for IAIC-treated Stage III b breast cancer patients.