Rio Branco Law

The Rio Branco law (Lei Rio Branco), also known as the Law of Free Birth (Lei do Ventre Livre), named after its champion, prime minister José Paranhos, Viscount of Rio Branco, was passed by the Brazilian Parliament on 28 September 1871. It was intended to provide freedom to all newborn children of slaves, and slaves of the state or crown. However, children of enslaved women in Brazil were obligated to serve their mother's owners until the age of 21, a condition that was often more or less that of slavery. The law did not define the exact legal status of enslaved women's wombs; this was negotiated by enslaved people afterwards, with women at the forefront.

The law was the beginning of an abolition movement in Brazil, but it turned out to be more of a legal loophole than a radical measure that led to viable progress. Only a few people were freed under the law, while more than one million people continued to be held as slaves throughout Brazil. This law had more of an influence in the northern part of the country, which was leaning further toward wage rather than slave labor.

Many of those freed under the Rio Branco law migrated to the north to work for wages on the plantations. The Rio Branco law was the first step toward abolition of slavery in Brazil. It was ultimately abolished on 13 May 1888 with the adoption of the Lei Áurea.