For evaluating the predictive value of experimental chemotherapy of human cancers xenografted to nude mice, two types of comparison between experimental responses in nude mouse system and their clinical results were made. The responses of 12 experimental therapies with single agent or drug combination were directly compared with those of the same kinds of therapy in each donor patient. Satisfactory agreement between the two results was shown in every comparison, with 3 true positives and 9 true negatives. Using 15 human cancer lines consisting of 7 gastric, 3 colorectal, 2 pancreatic and 3 breast cancers, single agent treatment with 6 drugs (MMC, ADR, ACNU, FT-207, 5'-DFUR) were performed. The effectiveness of each drug to these xenografts was in good accordance with the known clinical effect of each drug in the same type of cancer. Nude mouse-human cancer panel is useful for the secondary screening of the new drug.