Transparent diamond-like carbon (DLC) films were synthesized on glass using radio frequency plasma enhanced chemical vapor deposition method from the gas mixture of CH4, SiH4 and Ar. The pressure, the rf-power, CH4/SiH4/Ar ratio, and the deposition time were 0.1Torr, 100W, 20 : 1 : 1, and 20 min, respectively. The optical transmittances of DLCdeposited glass and uncoated glass were compared with each other in the visible light regions. The DLC-deposited glass showed transmittance of approximately 83 % and 95 % as compared to the uncoated glass for the wavelength of 380 nm and 500 nm, respectively. The hardness and roughness of DLC-coated glass have been measured by nanoindentation and AFM, respectively. The DLC-coated glass showed a little less or similar optical transmittance compared to the uncoated glass, while the hardness of DLC-coated glass was 2.5 times higher than that of the uncoated glass. The deposited DLC film had the very smooth surface and was thicker than 150 nm after deposition for 20 min.