Officials have called on voters to cast their ballots to deter "enemies." Supreme Leader Ayatollah Ali Khamenei has even called voting "a religious duty."
Despite such statements, many voters remain indifferent and some are still undecided about whether to vote.
Iranians calling a Radio Farda show remained divided. Atefeh from Ahvaz said people should vote.
"People should definitely go to the polls and by writing the name of Dr. Mustafa Moin on the ballots in order to shake up society. We shouldn't let our rights be violated by not voting and by letting them bring a president to power that we don't want," Atefeh said.
But another caller, Saeed, believes there is no point in voting.
"People should boycott the elections. This establishment doesn't do anything for the people. Mr. Khatami didn't do anything and Mr. Moin and the others cannot do anything either. It's all a show," Saeed said.
Some say they will not vote because they feel their vote doesn't count. But others warn that an election boycott will help the conservatives.
Turnout is expected to be lower than the last presidential election in 2001 when about 66 percent of eligible voters cast ballots.
Although President Khatami was reelected last time with some 70 percent of the vote, some believe that in Friday's polls none of the candidates will gain the needed 50 percent support to win. If that happens, it will be the first time since the 1979 revolution that the elections will go to a second round.
Rafsanjani, who heads the powerful Expediency Council, is leading in the polls. Former police chief Mohammad Baqer Qalibaf and former Education Minister Moin are seen as the strongest challengers.
Rafsanjani, 70, is considered a pragmatic technocrat who can liberalize the economy. He has pledged to solve economic problems, including providing jobs for the country's youth. He has also promised more personal freedom.
"Economic issues, including employment and inflation, are very important for people, and also development issues for those who like their country. People want to be at ease, they don't to be bothered by anyone," Rafsanjani said.
Rafsanjani has also spoken out in favor of reestablishing ties with Washington. But he says Washington must first end what he calls its hostile policy toward Tehran.
Qalibaf, a 43-year-old conservative running as an independent, is credited with improving the image of the police force. He was one of the revolutionary guard commanders who in 1999 warned Khatami that if he did not take firm control over student demonstrations, the guards would.
Qalibaf's campaign slogan is "good life suitable for Iranians."
"We will succeed in solving the problems we face now, and we will certainly do this by involving all the people in economic, political, and social issues," Qalibaf said.
Moin, 54, is the candidate of Iran's main reformist party. As education minister he strongly criticized pressure on students. He has indicated that if elected -- unlike his predecessor -- he will challenge the hard-liners. He has also pledged to tackle human rights abuses and to resume ties with the United States.
"Young people make up 70 percent of our population and they are Iran's greatest assets. However, we are only narrow-minded if we stare at oil wells and forget about human beings," Moin said.
The two other reformist candidates are former parliament speaker Hojatoleslam Mehdi Mahdavi-Karrubi and Mohsen Mehralizadeh, who heads the country's sports administration.
The three remaining candidates are from Iran's conservative camp. They include former state broadcasting chief Ali Larijani, Tehran mayor Mahmud Ahmadinejad and former head of Revolutionary Guard Mohsen Rezai.
The campaigning has been large, colorful, and creative with all candidates focusing on Iran's youth. One candidate has used roller-blading youth to distribute leaflets while another has promised a monthly $80 stipend for all Iranians over age 18.
Alex Vatanka, an analyst with Jane's Information group, recently traveled to Iran. He told RFE/RL that despite the campaigning, many Iranians remain uninformed about the candidates' programs.
"There are lots of anecdotal evidence that gets passed on, gets manipulated, so what I'm pointing to here is lack of information, lack of time to read about these things. People of Iran are increasingly running around trying to make ends meet and for them to spend a lot of time to actually, adequately get to know the candidates and so on is probably an investment most of them are not willing to make," Vatanka said.
In the runup to the poll, Iran has been shaken by a wave of bombings that have left 10 dead. Moin has said the violence was designed to weaken his support by creating a low turnout or making people choose a "military" candidate.
Vatanka says the bombings could create fear among some voters.
"People just don't necessarily think it's worth it because they don't think their voting will make much of a difference. Why should they put their lives in danger just in case something should go off. We haven't had bombings on this scale since the end of the Iraq-Iran war so a lot of people probably fear for their own safety," Vatanka said.
Human Rights Watch has said that the Iranian election will not be free and fair because candidates from outside the ruling elite are prevented from running.
RFE/RL Special: Iran Votes 2005