Born on 25 August 1934, a Shia clergyman and supporter of Ayatollah Khomeini, Rafsanjani was imprisoned several times during the 1960s and '70s for his political activities.
He is considered the most probable candidate to win the election, when on 10 May 2005, after long and controversial discussions, he announced that he would run again in the 2005 Iranian presidential election.
After the ouster of the Shah - Muhammad Reza Shah Pahlevi - Rafsanjani helped found the Islamic Republican Party and built his political power base as speaker of parliament from 1980 to 1989.
From 1988 to 1989 he was also acting commander-in-chief of the armed forces.
On 17 August 1989 Rafsanjani was elected president, receiving some 95% of the vote.
A conservative, he sought to revive Iran's flagging economy on free-market principles and moved to improve relations with the West, re-establish Iran as a regional power, and gradually reopen the country to foreign investment.
Rafsanjani tried to re-establish
Iran as a regional power
He was re-elected in 1993 with two thirds of the vote but was barred from seeking a third term in the 1997 elections.
That year he was appointed chairman of the Expediency Discernment Council, which is responsible for resolving disputes between the parliament and Guardian Council concerning legislation.
In 2000 he was narrowly elected to parliament, but he soon resigned his seat.
In the 2005 elections, many see him as a mid-ranking cleric, trying to re-brand himself as a liberal in a country where half of the 67-million population is under 25 and the voting age is 15.
At a round-table discussion group, when asked what he thought about relationships between the sexes, Rafsanjani said religion should be no barrier.
"In the Islam I know, if implemented, no one would feel limited in their instincts," said Rafsanjani, who has in the past spoken in favour of muta (temporary) marriage - a practice that allows Shia Muslims to wed for as little as a few minutes.
He has opposed harsh Islamic penal codes and promoted better job prospects for women in Iran.
Rafsanjani has three sons, Mohsen, Mehdi and Yasser, and two daughters, Fatemeh and Faezeh.