The authors devised two different types of cisplatin (CDDP) delivery systems; namely, System A and System B. The anticancer efficacy with each system was examined using cancer-bearing animals. Seventy-percent deacetylated chitin (DAC-70) was used as the drug carrier in the system. Cancer-bearing animals were prepared by intra-peritoneally (ip) inoculating the MM-46 cancer cells to C3H mice. Each novel system was also ip injected to the cancer-bearing mouse, and then survival time of each animal was recorded to evaluate the anti-cancer efficacy of the system. Both Systems A and B were viscoelastic sol at 25°C and slowly changed to gel at 37°C. Four-week survival rate of each animal treated with the System was as follows: System A 6/10 (60%), System B 10/11 (90.9%), conventional CDDP alone 3/9 (33.3%) and non-treated 0/7 (0%). No signs of recurrence of ascites were encountered in the long-term survived animals treated with System A and B. Our newly devised systems provided a favorable antitumor efficacy in vivo. Now, we will carry out further studies by making a clinically applicable novel conjugated system, DAC-70 and CDDP.