Roh Moo-hyun's weeklong trip, which begins Sunday, comes amid heightened tensions over North Korea's suspected development of nuclear weapons and rising calls for the United States to cut its troops in South Korea.
Defusing the North Korean nuclear crisis will be the key topic of the May 14 White House summit between President Bush and Roh. The two leaders, both 56, are known for being plainspoken about their views on the government in Pyongyang.
Ban Ki-moon, Roh's foreign affairs aide, said he expected a successful meeting, saying "the two leaders are of the same age and have the same pragmatic leadership style. The chemistry is right between the two."
At a meeting in Beijing in late April, North Korea gave U.S. negotiators a long wish list of political and economic benefits it wants to get in return for giving up its nuclear ambitions. Washington is reviewing the proposal with its allies in Japan and South Korea.
Since his election last December, Roh has tirelessly called for reconciliation with North Korea and a peaceful solution to the North Korean nuclear crisis.
He bluntly criticized any possibility of U.S. military action against the North, saying such an attack would trigger a full-scale war on the Korean Peninsula that would devastate the South as well.
Mr. Bush says he seeks a peaceful solution too, but has not ruled out military action. Mr. Bush pulls no punches when criticizing North Korean leader Kim Jong Il, whom he accuses of "blackmailing" the world and starving his people while pursuing weapons of mass destruction.
The nuclear dispute flared in October when Washington said North Korea admitted running a secret nuclear weapons program in violation of a 1994 treaty.
During the Beijing talks, U.S. officials say, North Korea claimed it already has nuclear weapons and that it had reprocessed spent nuclear fuel for more weapons materials.
On Monday, Secretary of State Colin Powell said impoverished North Korea can count on support from other countries only if it curbs nuclear weapons programs and missile exports as well as other activities such as drug trafficking.
Last month, Australian authorities raided a 4,480-ton Pong Su ship, which they said was owned by North Korea's communist party, and charged its 29 crew members with aiding the import of $50 million of heroin into Australia.
On Tuesday, North Korea denied involvement in smuggling the heroin.
North Korean "has consistently been opposed to the misuse and smuggling of drug(s) and has nothing to do with the recent case," a Foreign Ministry spokesman was quoted as saying by the North's KCNA news agency.
Roh's trip to Washington comes at a sensitive time in the U.S.-South Korean alliance, forged during the 1950-53 Korean War.
By October, the Pentagon is likely to decide on a major realignment — and perhaps a substantial withdrawal — of forces in South Korea.
Several months ago, thousands of South Koreans held protests to demand more South Korean jurisdiction over U.S. troops after two girls were killed by a U.S. military vehicle.
Thousands of South Koreans, however, also have rallied in support of the U.S. military's presence as tensions have mounted over the nuclear crisis.
"Some people seem to think, 'We will all die if we don't have the U.S. military.' This is simply not true," Roh has said. "South Koreans are underestimating the self-defense capabilities of their own military."
There are 37,000 U.S. troops in South Korea. The U.S. Army said Tuesday it has extended for 90 days the stay of more than 1,800 of its soldiers in South Korea to maintain its force readiness.