Ikhwaniat or personal letters are a type of historical source that contains diverse and rich social data. These letters which are mostly written outside of the political power system, have a unique feature that based on the writer of the letter has the opportunity to talk with the audience about the issues of his life, the personal status of the audience, and the condition of contemporary society. With this information, it is possible to show social data and present an image of the social atmosphere in people’s daily lives. The purpose of this article is to read the text of the Ikhwani letters in Atabat Al-Katabah from the perspective of social history and identify the categories of social history found in this important source during the Seljuk period. The main question in this article based on the descriptive and analytical method, is what categories of daily life can be identified in these letters? Based on the finding research, the importance of Ikhwani letters for social history studies is revealed. Also, categories such as complaints and dissatisfaction with the social situation, the effect of heavenly and natural disasters on people’s lives, the social hierarchy of people and its interior layers, family issues, the effect of politics on daily life, and similar cases can be achieved in the Seljuq era society.