Chitosan-stabilized gold nanoparticles (Cs/Au) film was prepared by casting strategy without a need for reducing and/or stabilizing agents. The shape, size, and crystalline phase were studied using UV-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The nature of the interaction between the Cs and Au nanoparticles was studied using the Fourier transformer infrared (FTIR) spectroscopy. The as-prepared Cs/Au nanocomposite film showed high activity in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP)in the presence of an excess amount of NaBH 4 . Furthermore, the Cs/Au film is easily separable, as well as remains active after reused for 3 times. The Cs/Au nanocomposite film could be a promising candidate for various catalytic reactions. K E Y W O R D S4-Nitrophenol, catalytic reduction, chitosan, gold, nanocomposite