In order to develop a new therapeutic intervention for pancreatic cancer, we have examined the effect of gene therapy for pancreatic disease. The transfection of the gene for UPRT, a 5-FU-converting enzyme, resulted in a significant change in the sensitivity of pancreatic cancer cells against 5-FU, resulting in the decrease of the tumor volume disseminated in the abdominal cavity of mice. Although the production levels of vascular endothelial growth factor (VEGF) in pancreatic cancer cell lines are different, anti-angiogenesis gene therapy using a soluble form of VEGF receptor (flt-1) has been demonstrated to be a promising strategy for pancreatic cancer. The transfection efficacy is the crucial point for the success of gene therapy; therefore, it is necessary to develop a vector system for solid tumors. It has been revealed that replication-competent adenoviruses are not only a strong weapon themselves, but are also useful carriers of genes possessing anti-tumor activities as virus vectors specific to tumors without normal p53 function or intact Rb pathway. Determining whether these experimental results are universally true will require clinical trials in the future.