The process of transmitting patient medical information between djerent healthcare parties involves harmonizing multiple elements: addresses, certificates, patient IDs, communication protocol, message format, and documents/EPR to be exchanged Beyond the work done at the “information structure level” within CEN TC251, ISO TC21S, HL7 and DICOM, it is necessary to focus on the “basic medical communication level.” An original approach, based on the “Patient Envelope”, has been developed and successfully implemented for Oncology. The operator of the National “Réseau Santé Social” is now proposing a new “secure messaging” service supporting the “Envelope”-based communication. The authors are actively involved in standardization organizations' works, including EDI Santé, DICOM, IETF, and ISO TC 215. The current “envelope” format is compatible with all the e-mail clients. It will evolve to be based on the ebXML envelope, extended with a “medical header” containing HL7/EHRCOM Data Types and C-METS/GPICs. This document describes the results from a 3-year experience, as well as the different steps included in the project.