Mr Lee has promised a tougher stance towards North Korea
South Korean President Lee Myung-bak has set off for the United States, on his first overseas visit since taking office in February.
The conservative Mr Lee will be aiming to repair ties that were strained under his liberal predecessor, Roh Moo-hyun.
He will meet President George W Bush on Saturday in Camp David, becoming the first South Korean leader to visit the presidential retreat.
Mr Lee will also meet the Japanese prime minister during a stop in Tokyo.
Ties between the US and South Korea cooled under the previous government because of differences over North Korea and the war in Iraq.
The previous president, Roh Moo-hyun, pursued a policy of economic engagement with Pyongyang, under the so-called "Sunshine Policy".
But since taking office, Mr Lee has pledged a stronger line - vowing to link bilateral aid to progress on human rights and denuclearisation.
During his visit he will "open a new era of pragmatic diplomacy", a statement from his office said.