Abstract: Disclosed are low-molecular weight, water-soluble chitosan nanoparticles with folic acid conjugated thereto as a target ligand and a preparation method thereof. The nanoparticles can be simply prepared since the strong reactivity of the chitosan allows folic acid to be readily introduced thereinto. Also, the folic acid-conjugated, low-molecular weight, water-soluble chitosan nanoparticles can be useful as gene carriers because they are of low or zero-toxicity, have sizes suitable for use as gene carriers, can readily form complexes with DNA, allow high gene expression rates, and are excellent in targeting tumor cells which are rich in folic acid receptors.