The American Federation of Labor (AFL), founded in 1881, was the most prominent labor organization of the time. The AFL was initially reluctant to admit black workers, but it eventually admitted several all-black unions in the early 1900s. However, the AFL continued to segregate black and white workers within its unions, and it did not do much to address the discrimination faced by black workers.
The Congress of Industrial Organizations (CIO), founded in 1935, was more open to black workers than the AFL. The CIO organized workers in mass production industries, such as steel, auto, and rubber, where there were large numbers of black workers. The CIO also took a strong stand against discrimination, and it played a key role in desegregating the labor movement.
In 1955, the AFL and CIO merged to form the AFL-CIO. The AFL-CIO continued the CIO's commitment to civil rights, and it has played a leading role in fighting discrimination against black workers.