Iran election: How the ballot works
Nearly 50 million people are eligible to vote in Friday's elections in Iran - almost 70% from the capital, Tehran, and the major cities while about 30% of voters come from rural areas.
There are nearly 70,000 polling stations and, according to the authorities, nearly one million people are involved in making sure the vote will go smoothly.
All a voter needs to cast a ballot is his or her birth certificate, which will be stamped to show that they have voted.
Also, they will have to press their thumbs into an ink pad to make sure there are no repeat voters.
Voters will be given a ballot paper on which they will have to write the name of their candidate of choice.
Those who cannot read or write will be helped by those inside the polling stations - this is always the cause of speculation as a source of irregularity.
There will be observers from the interior ministry - the department in charge of holding the elections. There will also be observers from the constitutional Guardian Council, as well as representatives of the candidates.
But not all candidates have enough representatives to cover all polling stations.
There will also be mobile polling stations - buses with ballot boxes that will visit prisons, hospitals and similar institutions.
These are also a source of concern for many as they are a bit difficult to keep under observation.
There are no independent or foreign observer missions - Iran does not allow that.
The results will be reported by fax to the interior ministry's election headquarters where they will be added up before being released on live television.
In 2009 there was widespread suspicion that the authorities at the so-called "addition room" of the interior ministry virtually manufactured millions of votes in favour of President Ahmadinejad who was running for his second term in office.
Iranians will be watching the process very carefully this time.