Vietnamese Prime Minister Phan Van Khai has arrived in the US at the start of a landmark three-day visit.
The prime minister started his tour by visiting Boeing
He is the first Vietnamese leader to visit the US since the end of the Vietnam War 30 years ago.
Mr Khai is expected to meet President George W Bush on Tuesday to discuss trade, regional security, military co-operation and human rights.
Ten years after ties between the two countries were restored, the US is Vietnam's biggest trading partner.
Mr Khai arrived in Seattle on the US west coast, visiting the Boeing aircraft factory south of the city.
Vietnam Airlines is buying four Boeing 787 planes.
He is due to hold talks on Monday with Bill Gates from the software giant, Microsoft, also based in Seattle.
Roughly 100 people - mostly of Vietnamese descent - protested outside his hotel over the country's human rights record.
Mr Khai, 71, said: "In the 10 years, we have progressed a long way to create a foundation to enhance the relation into a new phase... a friendly relationship... a comprehensive co-operation for long-term stability for the benefit of both sides."
Since then, two-way trade has soared from $1.5bn (£800m) in 2001 to $7bn (£3.8bn) in 2004. Main exports to the US are fish, shrimps, furniture and coffee.
"The United States is a very important trade partner for Vietnam," Mr Khai said ahead of his visit.
He is expected to use the visit to accelerate negotiations with the US about its long-standing desire to join to the World Trade Organisation (WTO).
Mr Khai said membership would be mutually beneficial and "help create opportunities for US companies to do business better in Vietnam".
Washington is expected to use the visit to strengthen security and anti-terror cooperation in the region while raising concerns about Vietnam's human rights record, particularly on religious freedom.
But the legacy of the American War, as it is known in Vietnam, in which two million Vietnamese and almost 60,000 US troops died, still haunts both countries.
Mr Khai is due to meet Defence Secretary Donald Rumsfeld to discuss military ties, the search for soldiers missing in action and compensation claims for victims of the wartime chemical defoliant Agent Orange.