US magazine Newsweek said the journalist, Maziar Bahari, had been released on bail on Saturday.
Mr Bahari was arrested on 21 June and put on trial with reformists accused of plotting against the Iranian regime.
Iran's semi-official ILNA news agency reported that his bail had been set at 3bn rials ($300,000).
Iranian TV also said Mr Bahari had been freed, citing a judicial statement.
It was not immediately clear if the journalist was free to leave the country.
Newsweek said in a statement that Mr Bahari was expecting his first child on 26 October and that the mother had experienced serious health complications.
Humanitarian considerations were presumed to have played a role in the decision, it said.
Mr Bahari, 42, is a reporter and documentary maker who had been accredited to work in Iran for more than a decade.
He was arrested during the mass protests that took place after President Mahmoud Ahmadinejad was declared the winner in June 12 elections.
Opponents said the vote was rigged.
According to reports on Newsweek's website he had been held in Evin prison without access to his family or lawyers.
The ILNA report said he had been charged with plotting against the regime by sending false election reports, disrupting public order by participating in illegal gatherings, and holding classified documents.
Other reports have said the charges against him included espionage and acting against Iran's national security.
After trial hearings, Mr Bahari told a press conference that Western media had tried to foment a "velvet revolution" in Iran.
Critics have dismissed the trials that followed the Iranian demonstrations as show trials, arguing that any confessions that followed are without value.