The French mission to the recently opened Saddam Hussein airport also went ahead without formal UN approval - and the Americans called it a "blatant violation" of UN sanctions, which were imposed in 1990 after Iraq invaded Kuwait.
The flight follows bitter criticism of France by the United States over a similar flight from Paris on Friday.
The Russian plane is carrying humanitarian supplies, a youth football team and a number of Russian politicians.
Russia's deputy ambassador to the UN, Gennadi Gatilov, said Moscow informed the sanctions committee 10 days ago about the planned flight, but was not seeking authorisation.
"From the legal point of view, we believe we have the right to send it," he said.
The French mission to the recently opened Saddam Hussein airport also went ahead without formal UN approval - and the Americans called it a "blatant violation" of UN sanctions, which were imposed in 1990 after Iraq invaded Kuwait.
But the French ambassador argued that as the flight was neither commercial, nor carried cargo, it did not need permission, only notification.
Both France and Russia, close trading partners of Iraq before the invasion of Kuwait, want the sanctions eased or lifted.
UN exchanges
This is the second Russian plane in a week to fly to Iraq. Last Sunday, Russian oil company executives flew to Baghdad after clearing the flight with the UN sanctions committee.
The Russian airline Aeroflot is also planning to re-open offices in Baghdad in anticipation of resuming flights in the event of UN sanctions being lifted.
The French flight to Iraq, with about 60 French doctors, artists and sports personalities on board, sparked tense exchanges at the UN, partly because it had notified members but not waited for authorisation.
The US condemned the move it as a "clear defiance of the UN and its established procedures."
But France maintains that it is not trying to erode sanctions, but merely interpreting UN resolutions in a more liberal way than Washington and London.
'Surprise and regret'
The Dutch ambassador who heads the UN sanctions committee, Peter van Walsum, criticised France for rejecting his request to delay the flight.
Britain said its reaction was one of surprise and regret that the French team had not waited for a decision from the committee.
A second French group has announced plans for another flight on 29 September.