— Watermarking is present as an alternative to protecting digital data from people who are not responsible. This research aims to build an algorithms technique hides the information into digital documents and to extract with Watermarking method using DCT (Discrete cosine transform), This research is also expected to built a watermark technique that can add a watermark into digital documents with good image quality without reducing significantly or decreased quality of the image is still within a reasonable tolerance value. Viewed from change capacity, the format tif very good image because Watermarking process, having performed citra terwatermark (tif ) suffered substraction, while review of reckoning quality mse psnr, and using images citra bmp very good since the value of MSE on bmp image is the smallest and PSNR value is large. Keywords—Digital document, DCT, Watermarking , Algorithm, robust