Abstract : In this paper, we present a new approach for watermarking of medical image that we are trying to adapt to telemedicine. This approach is intended to insert a set of data in a medical image. These data should be imperceptible and robust to various attacks. It's containing the signature of the original image, the data specific to the patient and his diagnostic. The purpose of the watermarking method is to check the integrity and preservation of the confidentiality of patient data in a network sharing. This approach is based on the use the LSB (least significant bits) of the image and tools borrowed from cryptography.