The 400 Cuban doctors are part of Brazilian President Dilma Rousseff's "More Doctors" program joined, by several hundred physicians from Uruguay, Argentina, Spain, and Portugal and 1096 from Brazil itself.
All last week, major Brazilian cities were the sites of massive youth protests.
Tens of thousands of people filled the streets of Sao Paulo again on Tuesday night.
Brazil's government will now investigate human rights violations committed by the right-wing military dictatorship that ruled the country from 1964 to 1985.
Cuban President Raul Castro told reporters that, "For the first time in history we will have an organization of Our America."
Reports from Brazil charge that politics and real estate greed contributed to the worst natural disaster in the country's history.
Dilma Rousseff, a former fighter against Brazil's U.S. supported military dictatorship, won a runoff election on Sunday October 31 and will become the first woman president in the huge South American nation's history.
Workers Party presidential candidate Dilma Rousseff racked up the largest vote total in Sunday's presidential election in Brazil, though she barely missed the 50 percent mark necessary to avoid a runoff
Brazilian President Luis Inacio Lula da Silva signed the "Statute of Racial Equality."
Brazil will soon elect a new president, to replace current President Luiz Inacio "Lula" da Silva who is constitutionally forbidden from succeeding himself, all 513 members of the lower house of Congress plus two thirds of the 81 senators.