In the XVIth century, the foundations of a period rich with political, economic, cultural and religiousideological events were laid in the Eurasian geography. The events that took place in the Near and Middle East during this period revealed the new political map of the region. The leading states of this political map were the Ottoman Empire, the Azerbaijani Safavid state and the Shaybani-Uzbek state. These Turkish states have contributed greatly to the political and economic developments in the Eurasian geography by closely participating in the international relations system. The establishment of the Safavid state in Azerbaijan at the beginning of the XVIth century was a very important event in the Near and Middle East region. With the establishment of the Safavid state of Azerbaijan, the basis of the political and religious-ideological rivalry with the Ottoman Empire, which ruled the Anatolian region and its surroundings, was laid. During the rule of Shah Ismail, there were military, political and diplomatic relations between the Safavid state of Azerbaijan and the Ottoman Empire, and diplomatic representatives and ambassadors played a major role in resolving military conflicts between these states. In the periods when political problems occurred between the states, dozens of ambassadors were active between the parties in order to weaken this tension, and hundreds of letters were written. When we look at the historical sources of the period, it can be concluded that the language of correspondence and letters between the Safavid-Ottoman-Shaybani states was generally written in Ottoman Turkish, Qizilbash Turkish (Azerbaijani Turkish) and Persian. In this article, the official correspondence and the language of letters between the Safavid state of Azerbaijan and the Ottoman state during the rule of Shah Ismail were the subject of research.