Abstract: Modern telecommunication infrastructure supports the possibility of delivering quality health care without the physical presence of medical experts. The integrity of medical signals being transmitted through communication channels must be established before utilization. In this paper, we study the watermarking algorithms for electroencephalogram (EEG) and put forward a novel watermarking algorithm based on adaptive filter. The experimental results show that the watermark is invisible and the watermark algorithm is robust against the most common image manipulations, such as JPEG lossy compression, low-pass filtering, median filtering, Wiener filtering, noise addition and rotation.