The effective gene delivery to target cells is a basic challenge of gene therapy. In this review attention is focused on liposomal vehicles. They represent not only an alternative, but also an extension to the other methods of transfection where both biological and synthetic materials are utilized. The structural and phase transformations of lipids are generally inherent to nature and can be applied in practice. The liposomes could serve as a specific matrix for materials composed of proteins, polysaccharides, and various synthetic polymers. The investigation of structural polymorphism of lipids and DNA--lipid complexes is important for designing of effective carriers of genes and drugs.