Cystic fibrosis (CF) is the most common recessively inherited lethal disease among the Caucasian population. CF is caused by mutations in the CFTR gene. Although several organs and tracts are affected, severe lung disease is the cause of the most of the morbidity and mortality in CF individuals. Current treatment is aimed at slowing the inevitable progression of lung disease, rather than halting it, or preventing its onset. The isolation of the gene responsible for CF suggested the feasibility of new therapeutic possibilities based on the CFTR gene transfer to CF patients. At present, somatic CF gene therapy clinical trials, using mostly animals but also CF patients, are being conducted. Gene therapy development is restricted by the lack of the appropriate gene vector systems, which could be successfully used to transfer in vivo and protect the therapeutic gene. This is because of the many extracellular, intracellular and immunological barriers, which protect living organisms against invasion of foreign genetic material. Future improvement in gene therapy depends on the more effective ways of the gene transfer methods, creation animal models of the human diseases and development of strategies involved in the new gene construct formulation, which facilitate to control gene transcription activity.