At present, chemoterapy still achieves poor results in advanced pancreatic cancer and sometimes the patient's quality is impaired by useless chemotherapy. To improve this situation, we used the nuclear damage assay (NDA) as a chemosensitivity test for pancreatic cancer. We performed the NDA on percutaneous needle biopsy tissue obtained from 19 patients with inoperable advanced pancreatic cancer, and 16 of them were successfully assayed by the chemosensitivity test. We could get a positive response to the assay in 13 of the 16 patients. The 13 patients with a positive response were treated with the agent selected by the NDA, while 3 patients with no response were treated with 5FU. The outcome of chemotherapy was a complete response in one patient, no change in 5, and progressive disease in 7 of the patients showing tumor sensitivity in the assay. On the other hand, only progressive disease was found in the patients with no response in the assay. The survival rate of the former group was better than the latter (P<0.05), and the median survival time was 23.4 and 11.1 weeks, respectively. We also report in detail the patient with a complete response to VP-16, which is rarely effective against pancreatic cancer. These results suggest that NDA of percutaneous needle biopsy tissue might improve the efficacy of chemotherapy for advanced pancreatic cancer.