We established a model of orthotopic transplantation of human hepato-carcinoma. The tissues from human hepatoma LTNM4 were surgically implanted into the livers of 32 BALB/c nu/nu nude mice. These led to the development of tum or masses in the livers of 31 nude mice; the rate of success was about 96.8% (31/32). Furthermore, this model was applied to the studies on the tumor inhibitory action of DHAQ-PBCA-NS, a hepatic targeting preparation for anticarcinoma. Satisfactory effect was attained. The result has proved the applicability of this animal model to researches on hepatic targeting preparations against carcinoma.