The Iraq Museum, housing more than a quarter of a million pieces, lost 15,000 artefacts to looting following the US-led overthrow of Saddam Hussein.
"At a time when most news broadcast about Iraq is depressing and negative, it is with great pleasure to mark this important, positive achievement," said Samir Sumaidaie, Iraq's ambassador to the United Nations.
The items returned on Tuesday were Mesopotamian cylindrical seals used to authenticate tablets before the use of paper. Each is about 1 inch tall and estimated to date to between 2340 and 2180 BC.
They were found by a US customs officer in the suitcase of Yale- and Princeton-educated scholar Joseph Braude at New York's Kennedy Airport in June 2003.
Braude, author of a book on rebuilding Iraq, denied at first he had travelled to Iraq but later admitted he bought the seals on Baghdad's black market for $200.
"For me they are completely priceless. They are part of our history," Sumaidaie said.
About half of the artefacts looted from the museum have been retrieved. "We will not rest until they are all returned to their rightful place in Iraq," he said.
Braude pleaded guilty to three counts of smuggling and making false statements. In November he was sentenced to six months under house arrest and two years' probation.