Bioreducible polymers, which can be degraded in reducing environment due to the cleavage of internal disulfide bonds, have been developed for gene delivery systems. They show high stability in extracellular physiological condition and cytoplasm-specific release of genetic materials, as well as decreased cytotoxicity because cytoplasm is a reducing environment containing high level of reducing molecules such as glutathione. Based on these advantages, recently, many bioreducible polymers have been further investigated with therapeutic genes for the treatment of diseases and demonstrated promising results. This review will focus on the therapeutic gene delivery using bioreducible polymers and the evaluation of therapeutic efficacy for cancer, myocardial infarction, diabetes and miscellaneous diseases.