Mohammad-Hadi Bordhar was
arrested in Iran in December and reportedly said he wanted to
"evangelise by handing out 12,000 pocket bibles".He was accused of "crimes against state security".
After being baptised, the man had created a "domestic church" in his home in Rasht in northern Iran, Fides reported. Iranian police found books, CDs and more than 6,000 Bibles at his property.
Fides said he had already been arrested in 2009 and found guilty of apostasy but had since been released.
The Catholic news agency quoted non-governmental groups saying that interest in Christianity among young Iranians is worrying the authorities and that churches have been shut down.
The agency said Iran's new president, Hassan Rouhani, has raised hopes with his rhetoric about civil rights.
The Christian minority in Iran is tiny, estimated at less than one percent of the population.