SYNOPSISBoth advanced stage lung cancer and malignant pleural mesothelioma are associated with a poor prognosis. Although there have been advances in treatment regimens for both diseases, these have had only a modest effect on their progressive course. Gene therapy for thoracic malignancies represents a novel therapeutic approach and has been evaluated in a number of clinical trials over the last two decades. Strategies have included induction of apoptosis, tumor suppressor gene replacement, suicide gene expression, cytokine based therapy, various vaccination approaches, and adoptive transfer of modified immune cells. This review will consider the clinical results, limitations, and future directions of gene therapy trials for thoracic malignancies.