Gene therapy has been developed as a potential novel treatment modality for colorectal cancer. The preclinical data have been promising and several clinical trials are under way for colorectal cancer. Data from many phase 1 trials have proven the safety of the reagents, but have not yet demonstrated significant therapeutic benefit. In order to refine this approach, continuing efforts should be made to improve the antitumour potency, efficiency of gene delivery, and accuracy of gene targeting. It is likely that gene therapy will be integrated into pre-existing therapies including surgery, chemotherapy and radiotherapy to establish its niche in tomorrow's medicine.