Anticancer effects and biodistribution of a new lipophilic anticancer agent, estradiol-chlorambucil (KM2210), dissolved in lipiodol (LPD) were investigated as an intra-arterial chemotherapy (IAC) on Walker 256 carcinosarcoma grown in the liver of 136 Wistar rats. All rats treated with KM2210 (10 mg)-LPD survived for 90 days after administration, whereas none of the rats with LPD alone were alive for more than 19 days. Histological examination revealed that there was no viable tumor cell in the encapsulated necrotic tumor at 21 days after administration. There was no significant liver dysfunction or leukopenia due to KM2210. The biodistribution study using [14C, 3H]KM2210-LPD solution showed that KM2210 accumulated selectively in tumor and that the tumor-to-normal-liver and tumor-to-blood ratios were 10 and 1,000, respectively, at 21 days after administration. These results suggest that KM2210 has potential clinical application in the treatment of human liver cancer.