Correspondence is an activity to arrange relationship continuously between one to another, and be held with sending a mail each other. In this technonolgy era which develop increasingly, technology utilization has become important aspect in human life. One of sector which affected is in activity of incoming or outcoming mail on an organization. Therefore, it is necessary to build an application incoming and outgoing mail, which can facilitate the work of human in sending mail, archiving mail and classifying the mail corresponding related to the organization. Applications presented by clustering using K-Means, therefore this method can be used for large datasets or a small dataset