Gene therapy is used for developing strategies for the treatment of genetic diseases and it is a promising technique for people with incurable diseases. A successful gene therapy includes the transfection of plasmids with related transgenes into the target cells. The transfer of the DNA molecule to target cell is the main problem of the gene therapy studies which directed researchers to find an effective way of transfection. The transfection of DNA is commonly achieved by a vector because of the limited insertion ability of the DNA into the cells and the possibility of enzymatic degradation of DNA molecule. These vectors are grouped into two categories as viral and non-viral. Adenovirus, adenoassociated virus, herpes simplex and retrovirus are the main examples of viral vectors. Non-viral vectors are grouped into two as physical and chemical methods. The physical methods are microinjection, particle bombardment - gene gun, electroporation, sonoporation, laser beam and magnetofection. The chemical methods are consisted of liposomes which developed as an alternative to the viral vectors. These vectors must have three important features for the transfer of the related gene into the cell nucleus. Those are disguising the negative charge of the DNA, condensing the DNA molecule and protecting it from the intracellular nuclease activity. Non-viral transfection systems such as liposomes are preferred rather than viruses, because of being nonimmunogenic, ease in formation and simple scale-up process in industrial production. Liposomal vectors have a diversity in morphology and in release characteristics, which they can be used tissue targeting and they can protect plasmid DNA from the attacks of degradative nucleases. DNA - cationic lipid complexes were used in different DNA transfer protocols in various cell types since defined as a potential transfer system in 1987 and is still being researched for the clinical gene therapy studies. This review highlights the chemical and physical methods of gene therapy as a novel and promising technique for the treatment of cancer and genetic disorders.