It was a small, round-table discussion that followed recent declarations by the country's president that the Jewish genocide was a "myth" and that Israel should be wiped off the map.
The low-key event, hosted by a private news agency and a pro-Palestinian non-governmental organisation and attended by a few dozen people, was separate from a conference that the Foreign Ministry plans to examine evidence of the Holocaust.
The hard-line Association of Muslim Journalists has also proposed a similar conference. No date has been set for either conference.
"We wanted to review the issue in a scientific way since there is less room for discussion in the West," said round-table spokesman Mahdi Shakibai.
"Enlightening public opinion in this regard is a need due to some pressures on our government," Mr Shakibai said.
The round-table, "Holocaust: Reality or Myth," follows international condemnation after President Mahmoud Ahmadinejad late last year called the Nazis' World War II slaughter of European Jews a "myth" and said Israel should be wiped off the map or moved to Germany or the United States.
Holocaust debate
The three-hour event was a discussion between Ahmad Bakhshayesh, a political science professor at Tehran's Allameh Tabatabai University, and Shamsoddin Rahmani, a political researcher for the Society for the Defence of the Palestinian Nation, a little-known NGO that sponsored the event with the Qods news agency. It was attended mostly by university students.
Mr Rahmani called the Holocaust a lie used by Zionists to justify creation of Israel. Mr Bakhshayesh countered that the Holocaust had occurred but said the West had exaggerated the number of its victims.
He suggested that Iran should challenge Israel based on its oppression of Palestinians and not by denying history.
That comment, however, angered some of the student in attendance, who noisily attacked him.
"If we don't challenge Israel now, in the future it will challenge us. Israel attacked Iraq; maybe Iran is next," said 21-year-old Mahsa Rasouli.
Israeli warplanes destroyed an unfinished Iraqi nuclear reactor in 1981. Last week, Israel's defence minister said the Jewish state was preparing for military action to stop Iran's nuclear program.
Morteza Nematzadeh, an SDPN spokesman, stressed that the round-table was not an anti-Semitic gathering. "We only wanted to say that Israel was exaggerating the number of victims of the Holocaust and misused the event to occupy Palestine and violate the rights of Palestinians," he said.
Event organisers said they plan to hold more debates. Iranians are not traditionally anti-Semitic. About 75,000 Jews left the country after the 1979 Islamic revolution but some 25,000 remain, and are represented by a Jewish MP in parliament.
However, since taking office, Mr Ahmadinejad has pushed hard-core rhetoric against Israel.