Abstract: The object of the invention is a method for transmitting electronic mail messages securely encrypted to a recipient, to whom an unencrypted electronic mail to be delivered cannot be assured of its information security. In the method: the sender (C1) sends an electronic mail message (1) to an electronic mail server (M1) that is his own or that of a known organization using an encrypted electronic mail transmission protocol, and the electronic mail message is marked as secured mail by adding the domain identifier of the secured mail server to the end of the electronic mail address of the recipient, wherein the server M1 sends it as guided by the name service further, using an encrypted transmission protocol, to the secured mail server TP, which stores it. The secured mail server sends to the sender a dispatch acknowledgment request (2.1), to which the sender answers with a dispatch acknowledgment (2.