The AFL and CIO merged to form the AFL–CIO in 1955.
The American Federation of Labor and the Congress of Industrial Organizations had been rival labor federations. The AFL traditionally emphasized craft unions, while the CIO promoted industrial unionism and organized workers across entire industries. Their rivalry produced major disputes and competing organizing campaigns.
The merger brought the two largest U.S. labor federations together under one national organization. George Meany became the first president of the AFL–CIO, and Walter Reuther became its first secretary-treasurer.
The AFL–CIO is a federation of affiliated unions rather than a single union representing every worker directly. It remains a major voice for organized labor in the United States. The merger year is distinct from 1886, when the AFL itself was founded.