Silicone rubber films were surface-modified with O-2, Ar, or NH3 plasma in either a belljar-type or a tubular-type reactor to investigate the effect of the plasma treatment conditions on the hydrophilicity, peel strength, and chemical composition of the film surface. ESCA spectra of the modified films were used to calculate the elemental ratios of oxygen to carbon and nitrogen to carbon. In the belljar-type reactor, the order of hydrophilicity improvement was found to be O-2 > Ar > NH3 plasma. NH3 plasma treatment at 10 W for 2 min resulted in the highest enhancement of peel strength. The contact angle of water on the modified surface increased with storage humidity. However, the peel strength decreased with the storage time.