Based on understanding the molecular mechanism of bladder carcinogenesis, cancer gene therapy may well become a novel therapy in the near future. Currently, a viral vector system appears to be a better vehicle to deliver genes into target cells. Exploring different therapeutic strategies has generated promising results from preclinical bladder cancer models. Phase I clinical trials are underway to study the feasibility of this treatment for human bladder cancer patients. However, several potential problems associated with effective gene delivery need to be further refined.