Secretary of State Hillary Clinton has said the US will ease its import ban on Burma, as it emerges from years of political and economic isolation.
Ms Clinton made the announcement during a meeting with Burmese President Thein Sein on the sidelines of the UN General Assembly.
"In recognition of the continued progress toward reform and in response to requests from both the government and the opposition, the United States is taking the next step in normalising our commercial relationship," Ms Clinton said.
She said she hoped the move would provide more opportunities for the people of Burma, officially known as Myanmar, to sell their goods in the US market.
The announcement follows the Obama administration's resumption of normal diplomatic relations and the suspension of a US investment ban.
Burma's president said he was "very grateful" for the actions of the US.
Yesterday's meeting between Ms Clinton and Thein Sein was warm, a US State Department official said, speaking on condition of anonymity.
Ms Clinton offered US help in efforts for peace in Burma with its different ethnic minorities and in clearing mines from the country.
She also urged the end of Burma's military relations with North Korea.
The US Treasury Department last week removed individual sanctions against Thein Sein, a 67-year-old former junta member who emerged as the unlikely catalyst for a wave of reforms that were unthinkable a year ago.
The next step will remove more of the restrictions that isolated his country for two decades and squeezed its tattered economy.
Thein Sein's reformist, quasi-civilian government took office in March 2011, ending five decades of military rule.
It has started overhauling Burma’s economy, easing media censorship, legalising trade unions and protests and freeing political prisoners.
The US has responded with diplomatic and economic gestures.
Last week, veteran Burmese pro-democracy leader Aung San Suu Kyi was in Washington, where the Nobel Peace laureate was awarded the highest congressional medal of honour.
Ms Suu Kyi, who was kept under house arrest for 17 years, was released and subsequently elected to parliament in April, and has urged the US to ease sanctions to support the reform process.
US officials said that despite rapidly improving ties, they have concerns about political prisoners there, the government's slow steps to reconcile with restive minority groups in border areas, and ties to certain elements of North Korea's military.
However, they said they were confident that progress would continue on each of these issues.