"Everyone here today understands the importance of this issue to US-Vietnam relations and to the Vietnamese people," US Ambassador Michael Michalak said as he opened the week-long meeting, now an annual event.
US forces sprayed about 80 million litres (21 million gallons) of Agent Orange, which contains highly toxic dioxin, and other herbicides on southern and central Vietnam to deprive their enemies of forest cover and food crops.
Washington has rejected responsibility for the millions of people Vietnam says have suffered direct or second-generation disabilities due to Agent Orange, with US officials pointing to a lack of mutually agreed data.
However, in an effort to address the issue, US Congress in May 2007 set aside three million dollars "for environmental remediation of dioxin storage sites and to support health programmes in communities near those sites."
US and Vietnamese officials are now trying to determine how best to use the money.
At least three hotspots have been identified in the country that still pose a threat to public health -- in the southern city of Bien Hoa, the central city of Danang and Phu Cat, in central Binh Dinh province.
Separately, senior US State Department official Stephen Ganyard, on a visit to the country, raised the issue of how to clean up the hundreds of thousands of tonnes of mines and other munitions left over from the war, especially in central Vietnam.
"It could be a decade-long effort," Ganyard said.