Rapid advances in cancer gene therapy are driven by an explosive development of gene transfer technology and a strong demand for effective alternatives to unsatisfactory conventional cancer therapies. Discovery of the genetic basis of cancer has indicated that cancer is a disease of genes. Among a variety of approaches to gene therapy of cancer, anti-oncogene and tumor suppressor gene therapy of cancer are the two strategies that aim at correcting genetic disorders of cancer. The potential effectiveness of these approaches is promised by their precise targeting at the mechanisms of the disease. Successful examples of human lung cancer animal models by applying anti-K-ras retrovirus and recombinant p53 adenovirus are reviewed. Future development of these approaches towards clinical application is also discussed.