This chapter deals with the type of telemedicine that can be carried out using the widely diffused telecommunication channel of Internet. This is accomplished with an analysis of the advantages and limitations and the communication requirements of the medical professional. Personal collaborations through e-mail, group co-operation through newsgroups and mailing lists, multimedia data sharing through World Wide Web are described, with special attention to security and quality of service. A quick review on forthcoming Internet developments complements the issue. Some examples of the Medical use of Internet are included.