Eighteen N3 cases, fourteen skullbase invasion cases and twenty-six cases of paranasal sinus cancer with orbital invasion were treated by superselective intra-arterial chemotherapy using CDDP and sodium thiosulfate to preserve the organs and to improve poor prognosis. In these patients, 100-150 mg/m2 of CDDP was administered weekly to each feeding artery of the tumor superselectively at 5 mg/m. CT-arteriography (CTA) was used to diagnosis all feeding arteries of advanced cancers before infusing CDDP. Twenty-three of 26 cases with orbital invasion were treated with preservation of the eyeball. In three cases with extirpation of the eyeball CTA was not used in the treatment, and CDDP was infused into only the maxillary artery excluding the transverse facial artery. In skullbase invasion cases, the number of complete responses (CR) was 8/14, and that of partial responses (PR) was 6/14. Feeding arteries originating from the external carotid artery were found in 10 of all 14 cases by CTA, and four cases in which blood supply was from both carotid arteries were all anterior skullbase invasion cases. Ten cases with superselective intra-arterial chemotherapy originating from only the external carotid artery were significantly better responders than four cases originating from both carotid arteries. In N3 cases, feeding arteries were found in more than three arteries by CTA and the overall survival rate was 55%, calculated by the Kaplan-Meier method. CTA is a very efficient method for diagnosing all feeding arteries of advanced cancers in the superselective intra-arterial chemotherapy.