The Congress of Industrial Organizations (CIO) was an organization that covered under its arms many unions. One of the differences with American Federation of Labor(AFL) is that the CIO had the affiliation of a diversity of skilled and non-skilled workers, meanwhile, the AFL based its organization by the skills of its members.
In 1935, dissidents in the AFL founded the Committee for Industrial Organization. Sidney Hillman and John L. Lewis were the leaders of the movement. They gained the trust of their people with important organizing victories in rubber, steel, and automobiles industries.
Today, the AML-CIO are united. The merger of 1955 reunited almost 85 unions in the U.S. Its headquarters is in Washington D.C.