Venezuelan President Hugo Chavez and US Secretary of State Hillary Rodham Clinton have shaken hands in an apparently amicable encounter at a time of tension between the two countries.
They chatted and smiled at the inauguration of Brazil's new president.
Last week, Venezuela refused to accept the nomination of the new US ambassador to Caracas because of comments he made against the country.
Washington then revoked the visa of the Venezuelan ambassador to the US.
Mr Chavez later described his encounter with Mrs Clinton as a pleasant one.
"We greeted each other," he told reporters at Brasilia's airport. "She had a very spontaneous smile and I greeted her with the same effusiveness."
Mr Chavez has not responded to the US government's decision to revoke the visa of Ambassador Bernardo Alvarez.
The two countries have long had reduced contacts due to the antagonism fed by Mr Chavez's condemnations of the US and by the US state department's criticisms of democracy in Venezuela, observers say.