Preparation of transparent water-repellent films was carried out using th ree kinds of fluoroalkyl silanes (FASs) by radio-frequency plasma-enhanced chemical vapour deposition. The effects of the reaction conditions on the structures and properties of the films were studied. The films prepared showed high water repellency like poly(tetrafluoroethylene). The contact angles for water drops were about 107 degrees. The obtained contact angles depended on the length of perfluoroalkyl groups (CnF2n+1-) in FASs. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to investigate the film properties. The existence of the fluorine-containing groups such as -CF3, -CF2- and > CF- was confirmed at the fi Im surfaces. The contact angle decreased when oxygen was added to the plasma because of the decrease in the fluorine concentration in the deposited films by the decomposition of C-F bonds. The transmittance of the polycarbonate substrates coated using FASs was improved. The films also acted as an antireflective coating.