The absence of effective therapies for hormone refractory prostate cancer establishes the need to develop novel therapeutic modality, such as a gene therapy, that can be applied either separately or in conjunction with current treatment modalities for the treatment of advanced prostate cancer. About 80 protocols for prostate cancer gene therapy have been practiced since 1994. The gene therapy modality is ideal for the treatment of prostate cancer. The disease progress can be precisely monitored by serum-PSA level, the local access is easy by ultra-sound guidance, and prostate as an accessory organ is highly immunogenic. Consequently, the number of prostate cancer gene therapy trials is increasing now. In this paper, we review the previous clinical trials of prostate cancer gene therapy in the chronologic order, and predict the future prospects.