Médicos Sem Fronteiras (MSF) (Doctors Without Borders), is an international organization committed to bringing aid to people who need it most in the world. It was formed in 1971 in France, by a number of doctors and journalists as a medical organization, combining medical help with public awareness about humanitarian suffering. In 1999 MSF won the Nobel Peace Prize.

The organization primarily provides specialized and high quality medical care, but in some specific cases of extreme emergency it also provides water, food, sanitation and shelter.

MSF arrived in Brazil in 1991 to combat a cholera epidemic in the Amazon. The first urban intervention took place in 1993 in Rio de Janeiro, with a project to help children living on the streets, and since then it has developed 15 projects across the country.