The Portuguese State and the Ottomans first encountered each other in the military field in the 16th century. In the 17th century, the dimension of these relations shifted more to trade. During the Napoleonic Wars, the Kingdom of Portugal wanted to make a trade agreement with the Ottoman Empire. Analysing the political balances, the Ottoman Empire decided to postpone this request for a while without rejecting it. Later, due to developments such as rebellion and civil war in Portugal, this agreement could not be concluded until 1843. On this date, an agreement called "Friendship, Trade and Navigation Covenant" was signed by the Portuguese ambassador in London and the Ottoman Empire's Ambassador to England, Mehmed Emin Acirc;li Efendi. During this agreement, some diplomatic innovations such as the presentation of engagement were also implemented. The mentioned treaty was prepared largely in accordance with the Ottoman-Belgian Peace and Trade Treaty, which was first drawn up in 1838 and later revised in 1840. Therefore, this agreement is similar to the Balta Limani Trade Agreement made between the Ottoman Empire and England, which is an example of trade agreements made with European states since 1838. While some articles of this trade agreement offer privileges directly to the Portuguese, they do not comply with the principles of reciprocity. In particular, Article 8 contains privileges that would undermine the independence of the state. The political and diplomatic process and the transactions that continued until the signing of this treaty constitute the subject of this article. The aim of the study is to reveal the nature of Ottoman-Portuguese relations in the first half of the 19th century. The reflections of the diplomatic skills and political considerations of the Ottoman Foreign Service were analysed in the light of official documents in the Ottoman Archives (Prime Ministry Ottoman Archives). Copyrighted works that serve as sources were also used in the study.