Cords have commonly been used as reinforcing materials in rubber composites. To improve cord/rubber interfacial adhesion, the cords are usually coated with an adhesive (typically based on Resorcinol-Formaldehyde-Latex(RFL)). These cord/rubber composites have been used in many sectors such as the tire, hose and belt industries. Interfacial adhesion between cord and rubber is an important determinant of the durability of the composite system. In this study, newly developed polyketone cord was coated by dipping in various RFL-based adhesive primers and then bonded to natural rubber by a compression molding method. The resin/latex ratio in the RFL adhesive primer was varied in order to achieve the optimal mixing ratio. Polyketone cord was treated with primers at various heating temperatures and dipping times. To measure the adhesion strength between the polyketone cord and the natural rubber, and the fatigue resistance of the composite system, the H-test and the tension-compression test were performed. The surface of the polyketone cord treated with primer was examined by attenuated total reflectance (ATR) spectroscopy and other instrumental techniques.