Abstract: A primary human renal cell carcinoma was developed as a xenograft （NT-25） which has een maitained by serial transplantation in nude mice. The effect of UFT and FT-207 on this eogrowth in nude mice was tested and evaluated. The distribution of the the drugs in the issue f the animal was also examined. The concentration of UFT was proven higher in tumor tissue han hat in other tissues and in the animal experimentation UFT was found to be effective on human enal cell carcinoma.