Recent advances in molecular biology have revealed that a number of oncogenes (K-ras, erbB-2, and Met) and tumor suppressor genes (p53, p16, APC, and DCC) contribute to the development of pancreatic cancer. This paper reviewed the present knowledge of oncogenes and tumor suppressor genes relevant to pancreatic cancer. Further studies on molecular alterations in pancreatic cancer may lead to a better understanding of tumor biology, offering a possibility of development of new diagnostic and therapeutic approaches in the future.