The letter is one of the communication tools that are used to convey information in writing from one party to another party either personally or on behalf of the organization in accordance with the applicable rules. Given the importance of the role of the letter, they are as a tool of written communication, as authentic evidence, as a reminder, etcetera so that must a good handling and be correct letter. The purpose of this final project is to determine how to manage incoming and outgoing mail management at PT Pelayaran Nasional Indonesia (Persero) branch of Semarang. Method of data collection is by observation, interviews, and literature. Types of data used is qualitative data, whereas for the preparation method of this thesis is descriptive. Management of incoming mail at PT Pelayaran Nasional Indonesia (Persero) branch of Semarang including letter receive, letter sorting,letters recording ,letters distributing mail, and mail storage. While the management of outgoing mail at PT Pelayaran Nasional Indonesia (Persero) branch of Semarang including letter concepting, letter typing, letters recording, storage and delivery of letter mail. Letter form used in PT Pelayaran Nasional Indonesia (Persero) branch of Semarang is a new form of indonesian official.