ran's supreme leader, Ayatollah Seyed Ali Khamenei, granted amnesty to 649 convicts on the occasion of Eid al-Ghadir, a Shiite Muslim festival, according to the semi-official Fars news agency.
The Iranian constitution grants the supreme leader the right to pardon or reduce the sentences of convicts upon a recommendation from the head of the judiciary, Fars said.
In this case, the country's Judiciary Chief, Ayatollah Sadeq Larijani, requested the amnesty, it said.
It was not immediately clear whether the Iranian woman whose death sentence has sparked an international outcry outside Iran was among those granted amnesty.
Sakineh Mohammadi Ashtiani was convicted of adultery in 2006 and sentenced to death by stoning. The Iranian government also said Ashtiani was involved in her husband's murder, a charge her family has denied.
Human rights groups and various governments have urged Iran not to execute Ashtiani. Earlier this month, European Union High Representative Catherine Ashton demanded that Iran stop the execution from going ahead and convert her sentence, and British Foreign Minister William Hague called the proposed stoning a "barbaric punishment."
Ahstiani, a 43-year-old mother of two, has said that while she was convicted of adultery, she was acquitted of murder and that the man who killed her husband has been imprisoned.