In this study, unlike synthetic polymers with toxicity. we used low molecular water soluble chitosan(LMWSC) having a free amine group for gene delivery. The LMWSC efficiently condensed plasmid DNA into mamosized ion-complexes. An investigation of gene condensation and the stability of complexes were performed by a gel retardation assay. The size and zeta potentials of complexes were measured by dynamic light scattering(DLS) Cytotoxicity of complexes was performed by MTT assay usign 293T cell and HeLa cell.