Dr Rouhani is set to deliver a speech on the first day of the summit. Upon his arrival at the Istanbul airport, President Rouhani was welcomed by Turkish Economy Minister Mustafa Elitaş,
Iranian Foreign Minister Dr Mohammad Javad Zarif and Iranian Ambassador to Ankara.
The 13th Summit of the Organisation of Islamic Cooperation is scheduled to kick off on April 14 and 15 in Istanbul.
The 13th OIC summit has started on Thursday at the Istanbul Congress Center, with Turkish President Recep Tayyip Erdogan as hosting leader.
Combatting terrorism and extremism is one of the issues to be discussed in the summit.
During 2-day meeting, Rouhani will have bilateral meetings with a number of his counterparts on the sideline of the meeting.
The OIC foreign ministers held meeting prior to the Summit in presence of Iranian Foreign Minister Mohammad Javad Zarif.
President Rouhani arrived in Istanbul Wednesday night. Uppon his arrival President Rouhanin said that Muslims of the world expect the Summit of Leaders in Istanbul to echo the voice of unity, solidarity and cooperation of the Muslim World.