Plasma pretreatment was applied to polyurethane-coated leather and polyurethane foam to improve adhesion. The optimum condition of the treatment was examined, and its performance was compared with conventional treatment techniques. In addition, optical observation was conducted to investigate the surface change from the treatment. In the case of polyurethane-coated leather, longer treatment time gives better adhesion, but a ten-second treatment works best for polyurethane foam due to its low contact angle. Excessive oxygen flow during plasma treatment does not enhance performance. It is shown that the plasma treatment reduces the contact angle to result in an improvement of peel strength. Also, optical observation indicates surface change and wettability increase.