Voters will take part in two separate ballots -- one to elect members of parliament and another to pick the Assembly of Experts, a powerful committee of 88 clerics who supervise the work of supreme leader Ayatollah Ali Khamenei, Iran's ultimate authority.
The run-up to voting day on February 26 has been dominated by controversy over who will be allowed to contest the elections rather than actual debate of the policies that candidates support.
All those seeking public office in Iran are vetted for their loyalty to the Islamic republic and almost half the applicants seeking to become candidates were excluded.
In the initial round of vetting, reformists suffered the heaviest blow, with thousands of candidates excluded.
That decision -- taken by the Guardian Council, a watchdog that scrutinises and has veto power over who can stand -- was criticised by Hassan Rouhani, Iran's moderate president whose nuclear deal with world powers stands to open Iran up to the West.
After Rouhani and government ministers intervened, 1,500 rejected candidates were reinstated.
But grievances remain, particularly because of the exclusion of many prominent reformists.
Emphasising the tightly controlled nature of Iran's elections, the application and vetting process has taken seven weeks while the parliamentary campaign will last only a week.
On the first official day of campaigning on Thursday, there were few posters on the streets and those that were visible represented candidates for the Assembly of Experts rather than parliament.
Would-be lawmakers are not allowed to make speeches in the street, and at venues where they are permitted to address voters or supporters, placards, posters or use of outside loudspeakers are forbidden.
Only 15-by-20-centimetre (six-by-eight-inch) posters of their credentials or policies are allowed to be put up or distributed.
MAY PICK NEXT SUPREME LEADER
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Reformists have urged their supporters to turn out in strong numbers despite the setbacks.
A pro-Rouhani coalition of reformists and moderates, on the back of the nuclear deal, is hoping to swing the balance of power in parliament away from conservatives.
Should the bloc -- the Alliance of Reformists and Government Supporters -- succeed, Rouhani would stand a better chance of delivering modest political changes and social reforms.
Although parliamentarians backed Rouhani on the nuclear deal they did so less out of a sense of support for the president than because Khamenei made it clear he wanted sanctions lifted.
The president's domestic plans have been blocked by lawmakers and one of his ministers was impeached, with replacements also being rejected.
Although 290 seats -- 30 in Tehran alone -- are up for grabs in parliament many see the Assembly of Experts election as having much greater importance.
Its current task is to monitor Khamenei's work but its much bigger role could be in picking his successor.
Should the 76-year-old supreme leader, who underwent prostate surgery in 2014, die during the next assembly's eight-year term it would be responsible for picking his successor.
Assembly hopefuls were also cut drastically by vetting. Of the 800 who applied only 161, all men, were approved by the Guardian Council.
Rouhani is seeking re-election to the assembly and is allied in two 16-member lists for Tehran headed by himself and former two-term president Ayatollah Akbar Hashemi Rafsanjani.
The two have become increasingly close since the build-up to the presidential election in June 2013 that saw Rouhani voted into office on Rafsanjani's backing.
Among those rejected for the Assembly vote was Hassan Khomeini, the 43-year-old grandson of the leader of Iran's 1979 Islamic revolution, Ayatollah Ruhollah Khomeini.
The younger Khomeini is a cleric with ties to reformist politicians.