Mendes was born in Xapuri, Acre, Brazil. He began working as a rubber tapper at an early age, and by the 1970s he had become a leader of the rubber tappers union. The union fought for better working conditions and wages for rubber tappers, as well as for the preservation of the Amazon rainforest.
Mendes's work brought him into conflict with powerful landowners and loggers, who saw him as a threat to their interests. In 1988, he was assassinated by gunmen hired by these landowners.
Mendes's death drew international attention to the plight of the Amazon rainforest and its indigenous peoples. It also helped to inspire the creation of the Chico Mendes Institute for Conservation and Biodiversity, a non-profit organization dedicated to protecting the Amazon rainforest and its biodiversity.
Mendes is considered a hero by many environmentalists and social justice activists. He is a reminder of the dangers that can be faced by those who fight to protect the environment and the rights of indigenous peoples.