State-run television announced the Guardian Council had barred all but six of more than 1,000 candidates, prompting reformists to threaten a boycott of the poll.
Among those eliminated are Mostafa Moin, leader of Iran’s largest reformist party.
Last year nearly 2,500 reformists were prevented from running in legislative elections, prompting a similar outrage and low voter turnout.
“We are warning the Guardian Council that we will not participate in the election if it doesn’t reverse its decision,” Rajabali Mazrouei, a top member of the reformist Islamic Iran Participation Front, told The Associated Press.
“Barring reform candidates means there will be no free or fair election,” he added.
But the announcement leaves reformers seeking democratic changes within the ruling Islamic establishment without a candidate.
The decision is widely seen as an attempt by Iran’s ruling clerics to consolidate their power following the departure of reformist President Mohammad Khatami, who is barred from seeking another term.
Though President Khatami came to power in a popular landslide in 1997, hard-line clerics led by Supreme Leader Ayatollah Ali Khamenei have succeeded in stifling his program for political and social reform.
The approved candidates for the June 17 poll include powerful former President Hashemi Rafsanjani, who is seen as a front-runner.
With the reformist movement effectively stifled, he’s seen as the most credible force to stop conservatives seizing the post of president.
The other approved candidates are former police chief Mohammad Bagher Qalibaf, former radio and television chief Ali Larijani, Tehran Mayor Mahmoud Ahmadinejad and former parliamentary speaker Mahdi Karroubi, former head of the elite Revolutionary Guards Mohsen Rezaei.
The Guardian Council barred women from running for the office.
The presidential election comes as Iran is facing international pressure over its controversial nuclear program, trying to convince the United States and Europe that it is not seeking to develop weapons.
Tehrn has vowed to restart some uranium reprocessing activities soon, saying it will unilaterally resume such activities if last chance talks with Europeans fail later this week.