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 (2.2), in which the sender notifies the mobile telephone number of the recipient or other contact information of the recipient differing from the electronic mail, in order to deliver a password (P2) to the recipient. The secured mail server (TP), upon receiving the acknowledgment of the sender, sends to the electronic mail address of the recipient a notification electronic mail (3), which notifies that a secured mail has arrived and the secured mail server sends further, using some communications channel other than electronic mail, a password (P2), with which the message can be retrieved from the secured mail server (TP). The recipient retrieves the message by an encrypted connection (5) using the information of the notification electronic mail and the password (P2) he received.