Carlos Ribeiro Justiniano Chagas was born in Oliveira, Minas Gerais, on July 9, 1878. He graduated from the Rio de Janeiro School of Medicine in 1903 and just two years later led a resoundingly successful campaign against malaria in Itatinga, São Paulo. Based on his so-called theory of household contamination, Chagas developed a new method for preventing malaria. His most outstanding achievement as a scientist was his 1909 discovery of American trypanosomiasis (now known as Chagas disease), an illness transmitted to humans by the kissing bug and caused by the protozoan Trypanosoma cruzi, which Chagas was likewise the first to describe. On the staff of the Oswaldo Cruz Institute since 1908, Chagas was appointed director following Cruz’s death in 1917, a post he held until his own demise. The first professor of tropical medicine at the Rio de Janeiro School of Medicine, he was also the first director of the National Department of Public Health (1919-1926). He passed away in Rio de Janeiro on November 8, 1934.