Venezuelan President Hugo Chavez says he expects to send an ambassador back to Washington soon.
Mr Chavez expelled the US envoy to Caracas in September in "solidarity" with Bolivia. The US reciprocated.
In response, the US state department says it "will now work" toward returning its ambassador to Venezuela.
The announcements came at a Summit of the Americas in Trinidad, where US President Barack Obama received a warm welcome from Latin American leaders.
Last September's diplomatic dispute arose over an alleged US plot against Bolivian President Evo Morales.
Mr Chavez was a fierce critic of the United States under former President George W Bush, accusing Washington of plotting to assassinate him.
But in a sign of warming ties, Mr Obama shook hands with President Chavez at the summit, and accepted a book from the Venezuelan leader.
Although they had already shaken hands when they met on Friday, Mr Chavez greeted him again on Saturday, this time pressing on him a book.
In taking the gift, Mr Obama assumed it was a book by Mr Chavez himself, he said later.
However, it was a Spanish-language copy of The Open Veins of Latin America: Five Centuries of the Pillage of a Continent, a book by Eduardo Galeano chronicling exploitation in the region.
Asked about his first meeting with George W Bush's successor, Mr Chavez said: "I think it was a good moment... I think President Obama is an intelligent man, compared to the previous US president."
It was unclear whether the two presidents would have a one-to-one meeting.
Addressing the summit earlier, Mr Obama had cautioned Latin American leaders not to blame all their problems on the United States.
On a sour note, Bolivian President Morales asked the US president to publicly repudiate an alleged plot to assassinate him that officials in Bolivia say they crushed this week.
Analysts say Mr Morales does not believe there was US involvement in the alleged plot. But he told reporters that since Mr Obama took office he has seen no change in US hostility.
"In Bolivia... one doesn't feel any change. The policy of conspiracy continues," he said.
Correspondents say the dominant issue so far has been US-Cuba relations.
Cuba is the only major Latin American country excluded from the summit and Brazil's President Luiz Inacio Lula da Silva said another summit without the communist country would be unacceptable.
President Morales said Cuba had the support of the entire world as a result of the US trade embargo against it and it was now time to abandon that embargo.
For his part, Mr Obama said he was ready to accept Cuban President Raul Castro's recent proposal of direct talks.
The US has not maintained high-level diplomatic relations with Cuba since Fidel Castro led the island's revolution in 1960.
But Washington recently eased its embargo, allowing Cuban-Americans to visit relatives in Cuba and send money home more easily.
"I think we're making progress at the summit," Mr Obama told reporters after the meeting on Saturday in Port of Spain, ahead of summit plenary sessions.
Summit leaders are expected to address the economic downturn and the region's energy and security needs at the talks, which end on Sunday.
Aides to the US leader say he hopes to squeeze one-on-one meetings into his schedule along with the plenary sessions and group gatherings.