The soldiers were returning to their base in a truck late on Friday when armed men attacked, the UN envoy to Haiti said on Saturday.
Envoy Edmond Mulet said: "Our troops were in a military truck when they were attacked,
"They returned fire but two Jordanian soldiers were killed," giving no further details.
The attack took place just outside of the volatile slum of Cite Soleil.
At least 14 UN soldiers have been killed since the June 2004 deployment of the 9,000-strong peacekeeping mission to stabilise the Caribbean country of 8 million.
The ambush comes amid an increase in violence and threats from armed gangs in Port-au-Prince after months of relative calm.
The UN force was deployed after a rebellion that ousted the president, Jean-Bertrand Aristide, in February 2004.