The verdict against Hashem Aghajari, who lost a leg in the 1980-1988 Iran-Iraq conflict, is likely to send shock waves through Iran's reformist movement, many of whom have defended his right to free speech.
"The verdict was handed to his family yesterday," lawyer Saleh Nikbakht told Reuters.
The decision came as the pro-reform Khatami is locked in a fierce struggle to break the stranglehold on power of hard-line rivals who control key institutions such as the judiciary, armed forces and mostly non-elected supervisory bodies.
Dozens of outspoken journalists and intellectuals have been jailed in the last three years in a conservative crackdown.
"This sentence is designed to intimidate reformists," pro- reform MP Ali Shakourirad told Reuters. "It is unacceptable, it is incompatible with the law, with Sharia and logic."
Following a closed trial without jury in the western city of Hamedan, Aghajari was sentenced to 74 lashes, eight years in jail and then execution.
His lawyer said he expected Supreme Court judges to throw out the sentence on appeal.
Aghajari, a 45-year-old history lecturer, angered conservative clerics by delivering a speech on "Islamic Protestantism" in which he compared the earthly powers enjoyed by Iran's clerical rulers with medieval Catholic Popes.
PEOPLE NOT MONKEYS
Particularly galling for the clerical establishment was his questioning of the Shi'ite Muslim practice of emulating senior clerics qualified to interpret the Koran.
"Are people monkeys to emulate someone else?" newspapers quoted Aghajari as saying.
Aghajari told the Emrooz news Web Site (www.emrooz.org) before his sentence: "They may put me in jail or assassinate me but they would achieve nothing from this. Those who will be hurt are the clerical establishment they claim to be backing."
Political tension is rising in Iran as Khatami gears up for a direct challenge to mostly unelected hard-liners in powerful positions within the state who have blocked his efforts to revamp the Islamic Republic for the last five years.
The president has introduced two bills to parliament aimed at limiting the power of the judiciary and curbing the right of a conservative body to vet election candidates.
Leading Khatami allies warn that conservatives may be planning to round up hundreds of reform activists following the arrest of dissident journalist Abbas Abdi last week.
"Abbas Abdi's arrest has intensified rumors that hard-liners plan to arrest hundreds of reformists," newspapers quoted the president's younger brother, Mohammad Reza Khatami, as saying.
Others said hard-liners were only waiting for a pretext, such as a possible U.S. attack on neighboring Iraq, to launch a massive crackdown.
"They are clearly looking for a chance to proclaim a state of emergency, which would provide them with a chance to arrest reformists, mainly parliamentarians, en masse," parliamentarian Reza Yousefian told Reuters. (Additional reporting by Parisa Hafezi and Khosro Nazari)