Merkel, who will meet with Brazilian President Luiz Inácio Lula da Silva, emphasized the importance of Latin America as a partner for Germany before her departure on Tuesday.
The two are expected to sign an agreement for cooperation on renewable energy.
Germany wants Brazil – the second-largest maker of biofuel in the world – to agree to standards on biofuel production.
Concerns about biofuel production in Brazil include destruction of rain forest and low wages for agricultural workers on sugar plantations.
After her meetings in Brazil, the German chancellor travels to Peru for a European Union-Latin America summit.
On May 20, she is to visit Columbia and Mexico.
Venezuelan President Hugo Chavez, known for his incendiary commentary on state leaders, called Merkel a political descendent of Adolf Hitler and fascism on Sunday. The German government has largely brushed off the comment.