As a communication means, letter plays a significant role in Shahnameh. This paper classifies the letters in Shahnameh into three categories in terms of communication levels: letter from superior to inferior, inferior to superior and letters exchanged between counterparts. This paper also discusses the components of these letters, which are usually different depending on the subject and the recipient, and also how they were initiated and delivered. Moreover, the subjects and materials mentioned by senders before and after writing the letter, stipulation of the name of sender and recipient, the seal and function of letters in Shahnameh are also dealt with. The present research mainly aims at becoming familiar with the history of letter writing in Iran before Islam and analyzing the letters in Shahnameh in order to set them as pattern for today’s correspondence. Given that Shahnameh’s letters show the method and customs of correspondence in Iran before Islam, description and explanation of their analysis can help to improve letter writing techniques.