George Galloway is facing suspension from Parliament for 18 days, after an inquiry by its standards watchdog.
MPs said he "damaged the reputation of the House" in his comments about the inquiry into his Mariam Appeal charity.
The suspension was the result of him "concealing the true source of Iraqi funding" and "calling into question" the integrity of standards watchdogs.
The anti-war Respect MP said he had been punished for his "robust" defence by "a jury of my political enemies".
Mr Galloway, who has always denied receiving money from Saddam Hussein's regime, added: "I'm not a punch bag. If you aim low blows at me I will fight back. That's what I have done and that's what I have been suspended for."
The MP for Bethnal Green and Bow was expelled from the Labour Party in 2003 following outspoken comments about the Iraq war and has claimed the inquiry was "politicised".
Speaking outside Parliament after the announcement, he said the commissioner had noted six times that "I did not benefit personally by a single penny from Iraq, from the oil-for-food programme or from any other Iraqi source".
He added: "It is clear that what really upset them is the fact I robustly defended myself."
He said there was "grotesque irony" that Parliament had refused to hold a full inquiry into the Iraq war, but had spent four years "censuring one of the leaders of the anti-war movement for the way that they conducted the anti-sanctions, anti-war campaign".
He said the Mariam appeal had three main donors - two kings and one wealthy businessman, adding: "I never covered up where the money came from, I never asked where the money came from."
Mr Galloway said Parliament should be giving him a medal, not a suspension, for his efforts to stop the Iraq war and "the massacre of hundreds of thousands of people".
MPs to vote
The committee has recommended he be suspended for 18 days from 8 October, after the summer recess - but it must be confirmed by a vote by MPs.
The inquiry by the Parliamentary Commissioner for Standards began in 2003.
But it was suspended during Mr Galloway's successful libel action against the Daily Telegraph, which had suggested he had received money from Saddam Hussein's regime in Iraq.
After considering the commissioner's report, the Committee on Standards and Privileges recommended Mr Galloway apologise to the House and be suspended for 18 days.
Commissioner Sir Philip Mawer said Mr Galloway had "consistently failed to live up to the expectation of openness and straightforwardness" and considered the inquiry part of an "attempted political assassination".
He said there was "powerful", if circumstantial, evidence that "a substantial part" of donations to the Mariam Appeal from its chairman, Jordanian businessman Fawaz Zureikat, "came from monies derived, via the Oil for Food programme, from the former Iraqi regime".
He said "Mr Galloway at best turned a blind eye to what was happening and, on balance, was likely to have known and been complicit in what was going on."
In its recommendation, the committee said Mr Galloway's "conduct aimed at concealing the true source of Iraqi funding of the Mariam Appeal" and towards those involved with the inquiry had "in our view damaged the reputation of the House".
Asked about the claim that he had concealed the source of funding, Mr Galloway told reporters: " A jury of my political enemies came to that conclusion on circumstantial evidence."
He also said, referring to cash-for-honours claims and the recent attendance of a convicted rapist at a party fundraising event, that "the people in the building behind me are the last people on earth to criticise" anyone over funding for political campaigns.
The Mariam Appeal was set up by Mr Galloway in 1998 to provide medicine and medical help to Iraqis during the last years of Saddam Hussein's rule and under international sanctions.
He and other trustees were criticised by the Charity Commission last month, for failing to make sufficient inquiries into the sources of donations.
It found the appeal had received significant donations connected with improper transactions made under the Iraqi oil-for-food programme - but said the money had been spent on humanitarian aid.
Mr Galloway and the other trustees have denied any wrongdoing and he said the report was "sloppy, misleading and partial".