Novel oligomeric silanes having end-capped fluoroalkyl groups have been synthesized. The glass surface was modified by oligomeric as well as by monomeric silanes. From contact angle measurements, the surface free energies were determined and the surface was shown to be both highly water- and oil-repellent. Oligomeric-type silanes were more reactive and effective than monomeric-type silanes. A linear correlation was observed between the area ratio of the F1s peak to the Si2p peak. The structure of the siloxane layer is discussed in terms of a network interphase model.