By lopsided 262-167, 300-129, and 278-151 margins, respectively, lawmakers backed the agreements and sent them to the Senate, which was on track to pass them swiftly despite opposition from the White House's labor union allies.
Obama has made passing the accords -- negotiated and signed some five years ago under his predecessor, George W. Bush -- a core part of his strategy to battle 9.1 per cent unemployment ahead of November 2012 elections.
"These agreements will support tens of thousands of jobs across the country for workers making products stamped with three proud words: Made in America," Obama said in a statement as he sent the accords to Congress last week.
The Obama administration said the deals are expected to boost US exports by USD 13 billion and benefit US agriculture and manufacturing, and will bolster diplomatic ties to all three countries.
It has also warned that the United States has seen its exports lose market share relative to global competitors like the European Union or China as those economies have secured new trade deals.
The pacts' Republican and Democratic backers were keen to pass them on the eve of South Korean President Lee Myung-Bak's visit to Washington, including a rare speech to a joint session of the US Congress today.
Lee and President Barack Obama were to travel to Michigan on Friday to tour a General Motors plant -- one source, Washington hopes, of future car sales to South Korea thanks to the agreement.
"These significant trade pacts will provide new opportunities for American small businesses, farmers, and manufacturers to expand and hire more workers," said Republican House Speaker John Boehner.
But many Democrats, notably from the hard-hit heartland, have expressed worries about possible US jobs losses.
"Now is not the time to pass more wrongheaded free trade agreements," said Democratic Senator Sherrod Brown, who represents the rustbelt state of Ohio. "We must put American jobs and American workers first."
