Incumbent President Mahmoud Ahmadinejad was not able to run for re-election as he was limited to two terms or 8 years in office under the Iranian constitution.

The President of Iran is the country's highest directly elected official, the chief of the executive branch, and the second most important position after the Supreme Leader.

Duties are similar to heads of governments in other countries, except that the armed forces, Chief judiciary system, state television, and other key governmental organizations are under the control of the Supreme Leader of Iran.

It is also an informal custom that cabinet ministers for sensitive departments like foreign relations and intelligence are coordinated with the Supreme Leader.

According to Iranian law, candidates more than 75 years old are eligible to run but their health issues must be checked by the Guardian Council.

[16][17] The following two candidates registered for the election and their nominations were approved by the Guardian Council, but withdrew their candidacies during the electoral campaign.

While Rouhani is a high-ranking member of the Combatant Clergy Association,[66] his candidacy in the election was not supported by CCA which has conservative tendency.

[68][69] From 25 May to 12 June 2013, each of the eight final candidates has the right to use National TV and Radio (IRIB) for their presidential election campaigns.

[74] The following table shows the programme details and the time schedule for each candidate in Iranian Public TV.

[79] On 9 June Brigadier General Seyyed Masoud Jazayeri, Deputy Chief of Joint Armed Forces Headquarters and head of the Defense Propaganda Headquarters, "warned" a "few of the candidates" that "we have warned before that it's better that candidates express their opinions within the framework of presidency's authority, and avoid entering in those issues related to security or the armed forces."

Jazayeri added that the Pasdaran will confront those candidates "who have spread untrue information and painted a black picture [of the regime], after the election."

According to the Campaign for Human Rights in Iran, Jazayeri was "alluding to the two reformist candidates in the race, Mohammad Reza Aref and Hassan Rouhani".

[82][83] The poll is based on the daily phone interviews with a sample size of around 1,000 people per day.

[84][86] On 10 June 2013 Ghalibaf still held a lead in the presidential race, but this time with the support of 27% of decided voters.

[87][88] On 12 June 2013 Rouhani made a notable lead in the presidential race, reaching 32% of decided votes.

[citation needed] Due to its massive population, Tehran province had the highest number of polling stations with over 17,000.

[129] Hours after the announcement of preliminary results, Ali Akbar Velayati and Mohammad Gharazi both conceded their loss in the election and congratulated the president-elect.

[130][131] Mohammad Reza Aref, the withdrawing candidate also published via his Twitter account, congratulating the new president and thanked people for voting for the reform movement.

[132] Hassan Rouhani, Mohammad Bagher Ghalibaf and Mohsen Rezaee's campaigns also thanked the nation on their high participation in the election.