The duty would hit imports including paper, agricultural, textile and machinery products from May 1, and affect slightly less than $28 million in trade, the European Commission said.
"The Commission took this latest step in the dispute over the Byrd Amendment in light of the continuing failure of the United States to bring its legislation in conformity with its international obligations," it said in a statement.
The level of EU retaliation would be revised annually to adjust to the level of damage caused to EU companies, it said.
It is not yet clear exactly which US products will be targeted by the 15% duty, although the Commission said it had also prepared a "reserve list" of products.
Commission officials said there were no plans to meet US officials before the additional duty came into force.
Neither was there a meeting planned between EU Trade Commissioner Peter Mandelson and US Deputy Secretary of State Robert Zoellick - until recently US trade representative - who is scheduled to be in Brussels early this week, they said.
In November, the World Trade Organization gave approval to the EU, Japan and others to apply an initial $150 million in trade sanctions after Washington failed to conform with a WTO ruling to repeal a subsidy program for US companies.
Known as the Byrd Amendment, the program distributes funds raised by anti-dumping duties on imports to the companies that initially requested government anti-dumping protection.
More than $1 billion has been doled out to US ball bearing, steel, seafood, candle and other companies under the Byrd Amendment over the past four years.
Canada is expected to announce similar measures against the US, its top trading partner.
The additional EU duty is the latest row to flare between the world's two trading giants.
Earlier this month, talks broke down between Washington and Brussels on subsidies enjoyed by aircraft rivals Airbus and Boeing before an April 11 deadline that was supposed to bury months of bitter wrangling.
Both sides accused the other, slamming the phone down on a conversation between Zoellick and Mandelson. (Reuters)
