Rouhani who is in Turkey at the official invitation of his Turkish counterpart will take part in the summit of the three presidents on Wednesday.
He is being received formally by his Turkish counter part Recep Tayyip Erdo?an in the Presidential Palace.
The president is also scheduled to hold separate discussions with Vladimir Putin and Recep Tayyip Erdogan, his Russian and Turkish counterparts respectively, on the sidelines of the trilateral meeting.
During the meetings, they are to explore regional and international cooperation as well as avenues for promoting bilateral relations.
Meanwhile, Foreign Minister Mohammad Javad Zarif arrived in Ankara at the head of a separate delegation today to attend a working breakfast with Sergei Lavrov and Mevlut Cavusoglu, his Russian and Turkish counterparts respectively, on Wednesday.
They will discuss the topics to be discussed by the three presidents and draw out draft for the summit.
The first round of presidential talks was convened in the Black Sea resort of Sochi in November 2017.
Moscow, Tehran and Ankara are guarantors of the Syria peace process, an initiative brokered in the Kazakh capital of Astana to find a peaceful ssolution to the Syria war.
