Ahmadinejad, who filled the role of the country’s chief executive for two consecutive mandates starting in 2005, signed up for the competition at the Election Office, which is based within the Interior Ministry’s premises in the capital, Tehran, on Wednesday.
He has already thrown his weight behind Hamid Baghaei, a former aide.
Ahmadinejad was accompanying Baghaei, who also went through the registration process.
Accompanying the two was Esfandiar Rahim-Mashaei, another former Ahmadinejad aide. The three were seen holding up their chained hands, shouting, “Viva spring, Viva Iran.”
Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei has advised Ahmadinejad not to run for president in the May elections, saying his potential candidacy would “polarize” the general atmosphere governing the country.
Ahmadinejad had also said he would submit to the advice and had “no plans to partake in the polls.”
The registration process began on Tuesday.