Iran's Ambassador to Brazil Mohsen Shaterzadeh announced on Thursday that Ahmadinejad and a large entourage of 110 representatives from 65 companies are to visit Brasilia on May 6.
"They are entrepreneurs in the oil, gas, petrochemical, agriculture, food, platform construction, mining and auto assembly sectors, among others, and will come to explore business opportunities in Brazil," Shaterzadeh told reporters.
Ahmadinejad is also expected to visit Venezuela in another leg of the same trip to Latin America.
US Secretary of State Hillary Clinton Friday called the development as "quite disturbing", and added, "I don't think in today's world, where it's a multi-polar world, where we are competing for attention and relationships with the Russians, the Chinese, the Iranians, that it's in our interest to turn our backs on our own hemisphere."
She blamed former US President George Bush's administration for what she claimed as "Iran and China's gains" in the region while she defended the new US President Barack Obama's strategy of reaching out to leaders such as Venezuelan President Hugo Chavez and Cuban President Raul Castro.
"The prior administration tried to isolate them, tried to support opposition to them, tried to turn them into international pariahs. It didn't work," Clinton reiterated.
Elsewhere, Clinton pointed to Iran's massive new embassy in Nicaragua, saying, "The Iranians are building a huge embassy in Managua, and you can only imagine what that's for."
In a response to Washington's accusations against Iran of using its friendly relations in the region for promoting terrorism, spying and weapons, Tehran has reiterated that the strong partnerships are the result of the United States' polices.
Iran's efforts to expand strategic relationship with countries in Latin America has been doubled during Ahmadinejad's government.