Turkish voters will cast their ballots on Sunday in the presidential run-off between the People's Alliance candidate President Recep Tayyip Erdogan and his rival, the People's Alliance's candidate, opposition Republican People's Party (CHP) leader Kemal Kılıçdaroğlu.
Polling stations open today at 5 a.m. (00:14 GMT) and close at 00 p.m. (<>:<> GMT).
More than 64 million Turks are eligible to vote at some 192,3 polling stations, and there are 4.20 million voters abroad who voted between May 24 and <>.
In the first round of elections on May 14, Erdogan received 49.5% of the vote, slightly below the majority needed to decide the first round.
Kılıçdaroğlu, the candidate of the six-party opposition alliance, won the support of 6.44 percent of voters, while nationalist candidate Sinan Ogan came third with 9.5 percent of the vote to be disqualified.
Hours before the election, Erdogan visited the mausoleum of former Prime Minister Adnan Menderes, who was executed by the military, and gave a speech where he described the coup against Menderes as depriving the Turkish people of democracy and leaving deep wounds in the country's conscience at the time.
Adnan Menderes (a prominent figure on Turkey's conservative right) ended in 1950 the rule of the secular Republican People's Party (CHP), founded by Mustafa Kemal Ataturk, the founder of modern Turkey, before being executed by the military.
Pro-Erdogan campaign rally in Istanbul (Getty Images)
In a tweet that coincided with his speech, Erdogan called on the Turkish people to achieve what he called "Turkey's great victory" by re-electing him in the run-off, and said that the votes that will give him victory "will inaugurate Turkey's new century."
Erdogan also visited the Sultan Eyup Mosque in Istanbul on Saturday and performed sunset prayers, and Erdogan arrived at the historic mosque accompanied by Parliament Speaker Mustafa Sentop, Interior Minister Suleyman Soylu and other officials from the Justice and Development Party.
At a subsequent rally, Erdogan urged his supporters to "cast their ballots starting in the early hours of Sunday morning" and persuade those who did not vote in the first round to go to the polls.
At a rally in Ankara, People's Alliance candidate Kılıçdaroğlu urged those he described as "those who love their country" to "protect the ballot box".
Kılıçdaroğlu criticized the Turkish government for what he described as "poor economic performance that has hurt Turkish families and prevented them from providing healthy food to their children."
In his speech, Kılıçdaroğlu promised to help women and families by establishing nurseries in Turkish neighborhoods, stressing that the establishment of nurseries is one of the state's social features, and promised to give needy families a monthly amount and not to cut off water, electricity or gas services to any needy family in Turkey.
Kılıçdaroğlu supporters rally in Ankara (Reuters)
Under election rules, news, speculation and commentary about voting are prohibited until 15 p.m. (00:18 GMT), and the media are free to publish election results from 00 p.m. (<>:<> GMT).
However, the Supreme Election Board may allow the media to report results earlier than this, and usually does.
Results are likely to be released today earlier than after voting in the first round, given the simplicity of ballots in which voters will choose between just two candidates, Erdogan and Kılıçdaroğlu.