Abstract: The challenges faced with printed image watermarking applications mainly are the robustness against distortion caused by print-scanning processing and the color fidelity of printed images. Based on the feature of CMYK color space and human visual system, this paper presents a robust CMYK printed image watermarking, which embeds the informative watermark and the structure template signal respectively in the Y color information channel and K color information channel. The embedded template enables the necessary robustness against geometric distortions in print-scanning process. A spatial perceptual mask is used to reshape the embedded energy after it is inverted to the spatial domain, which significantly improves the color fidelity and the image quality. A series of proof tests have been carried out on lithographic printing presses and shows that the watermark embedded in the CMYK images is well preserved and can be extracted with a high quality, and simultaneously, a remarkable fidelity of color and tones on printed copies is also well preserved.