In order to coat a sufficiently bonded barrier layer onto the inner surface of a rubber hose, plasma modification of the rubber surface prior to the coating was investigated. A stable plasma generation in the rubber hose was obtained when a piece of metal wire was inserted into the hose, while no plasma was available without a wire. Though the surface energy of the rubber was significantly increased by plasma exposure, it decreased with the extended treatment time. The rubber modified by oxygen plasma showed excellent adhesion to coated nylon compared with that treated in argon plasma. With this technique, a high performance, durable hose can be obtained.