Below is a list of unions affiliated with the AFL-CIO. Since the founding of the AFL in 1886, the AFL-CIO and its predecessor bodies have been the dominant labor federation (at least in terms of the number of member workers, if not influence) in the United States. As of 2014, the labor federation had approximately 12.7 million members.Form LM-2 Labor Organization Annual Report. AFL-CIO National Headquarters. File Number 000-106. June 30, 2008. Accessed 2009-09-19 As of 2015, the AFL–CIO had 56 member unions.

Historical context

AFL forms On December 8, 1886, the five-year-old Federation of Organized Trades and Labor Unions dissolved itself and became the American Federation of Labor (AFL).Dubofsky, Melvyn and Dulles, Foster Rhea. Labor in America: A History. 6th ed. Wheeling, Ill.: Harlan Davidson, Inc., 1999. Foner, Philip. History of the Labor Movement in the United States. Vol. 1: From Colonial Times to the Founding of the American Federation of Labor. New York: International Publishers, 1947. Foner, Philip S. History of the Labor Movement in the United States. Vol. 2: From the Founding of the American Federation of Labor to the Emergence of American Imperialism. New York: International Publishers, 1955. Rayback, Joseph G. A History of American Labor. Rev. and exp. ed. New York: Macmillan Publishing Co., Inc., 1966. In its first half-century, a large number of trade and labor unions formed, joined the AFL, and either merged with other unions or ceased to exist. Many unions, particularly those in the construction industry and affiliated building trades,Palladino, Grace. Skilled Hands, Strong Spirits: A Century of Building Trades History. Ithaca, N.Y.: Cornell University Press, 2005. disaffiliated from the AFL for a variety of reasons. Some rejoined; some did not.

Throughout the AFL's history, jurisdictional issues caused a number of disaffiliations.Foner, Philip S. History of the Labor Movement in the United States. Vol. 3: The Policies and Practices of the American Federation of Labor, 1900–1909. Paperback ed. New York: International Publishers, 1964. ; Foner, Philip S. History of the Labor Movement in the United States. Vol. 4: Industrial Workers of the World. Paperback ed. New York: International Publishers, 1965. ; Foner, Philip S. History of the Labor Movement in the United States. Vol. 5: The AFL in the Progressive Era, 1910–1915. Paperback ed. New York: International Publishers, 1980. ; Foner, Philip S. History of the Labor Movement in the United States. Vol. 8: Postwar Struggles, 1918–1920. Paperback ed. New York: International Publishers, 1988. In contrast to its early rival, the Knights of Labor, the AFL had adopted a policy of forming and admitting to membership (with a few limited, and notable, exceptions such as the United Mine Workers and Brewery Workers) only craft unions—unions whose membership was limited to workers with a single, narrow skill-set. But industrialization, with its emphasis on teams rather than individual workers manufacturing a product, disadvantaged craft unions in the drive to organize workers. A notable example was the effort to unionize the steel industry, where the Amalgamated Association of Iron and Steel Workers' adherence to craft unionism was a factor in the failure of many unionization drives.Brody, David. Steelworkers in America: The Nonunion Era. New York: Harper Torchbooks, 1969. ; Brody, David. "The Origins of Modern Steel Unionism: The SWOC Era." In Forging a Union of Steel: Philip Murray, SWOC, and the United Steelworkers. Ithaca, N.Y.: ILR Press, 1987. Some unions, including some large ones such as the Mine Workers, began advocating for a shift toward industrial unionism, where a union would organize all workers (regardless of skills) in a single company, market, or industry.Galenson, Walter. The CIO Challenge to the AFL: A History of the American Labor Movement. Cambridge, Mass.: Harvard University Press, 1960. ; Phelan, Craig. William Green: Biography of a Labor Leader. Albany, N.Y.: SUNY Press, 1989. ; Zieger, Robert H. The CIO 1935-1955. Chapel Hill, N.C.: University of North Carolina Press, 1995.

CIO splits, 1936–1955 The battle between the craft and industrial union philosophies led to a major membership loss for the AFL in 1935. In the first years of the Great Depression, a number of AFL member unions advocated for a relaxation of the strict "craft union only" membership policy but to no avail.Bernstein, Irving. The Turbulent Years: A History of the American Worker, 1933-1941. Paperback ed. Boston: Houghton-Mifflin Co., 1970. In 1932, Mine Workers president John L. Lewis privately proposed to several like-minded union presidents that those unions which wanted to organize workers on an industrial basis form a group to begin to do just that.Dubofsky, Melvyn and Van Tine, Warren. John L. Lewis: A Biography. Reprint ed. Champaign, Ill.: University of Illinois Press, 1992. The group met informally for three years, and lost a number of jurisdictional battles over potential or newly organized workers. Eight national unions formally organized themselves into the Committee for Industrial Organization (CIO) on November 9, 1935. On September 10, 1936, the AFL suspended all 10 CIO unions (two more had joined in the previous year) and their four million members. In 1938, these unions formed the Congress of Industrial Organizations as a rival labor federation.

Over the next 20 years, both the AFL and CIO would lose member unions. The AFL would purge some member unions for advocating industrial unionism (notably the United Auto Workers and the United Rubber Workers) or for supporting political philosophies it felt were antithetical to its purposes. It also reaffiliated some unions which had joined the CIO. The CIO, for its part, expelled a number of unions in 1948 after concluding they had become infiltrated by Communists (at least one additional union disaffiliated rather than be expelled). Both the AFL and CIO would form new unions to compete with those they had expelled, with varying degrees of success.

AFL–CIO, 1955–1999 By the early 1950s, however, the disagreement over craft and industrial unionism had largely ceased to exist. In 1955, the AFL and CIO merged to forming a new entity known as the American Federation of Labor–Congress of Industrial Organizations (AFL–CIO).Goldberg, Arthur J. AFL–CIO: Labor United. New York: McGraw-Hill, 1956. Over the next five decades, the AFL–CIO continued to gain and lose member unions. After a series of particularly divisive union raids on one another as well as repeated jurisdictional squabbles, the AFL adopted Article 20 of its constitution, which prevented its member unions from raiding one anotherLevey, "Union Raiding Ban Drafted By A.F.L.," New York Times, August 14, 1954.—a policy retained in the AFL–CIO constitution. Theoretically, violation of Article 20 could lead to expulsion, but corruption soon became much more important than jurisdictional issues. After hearings by the Senate Select Committee on Improper Activities in Labor and Management led to major revelations regarding the dominance of several AFL-CIO unions by organized crime, new rules were enacted by the AFL–CIO's Executive Council that provided for the removal of vice presidents engaged in corruption as well as the ejection of unions considered corrupt.Loftus, Joseph A. "Meany Summons Council to Weigh Beck Suspension." New York Times. April 17, 1956; Raskin, A.H. "Meany Wins Round Against Underworld." New York Times. April 29, 1956; Loftus, Joseph A. "A.F.L.-C.I.O. Votes to Curb Rackets." New York Times. August 30, 1956; Loftus, Joseph A. "Union Questioned On Hiding of Data." New York Times. January 18, 1957. The labor federation expelled the International Brotherhood of Teamsters on corruption charges on December 6, 1957."A.F.L.-C.I.O. to Go Ahead With Expulsion of Teamsters." New York Times. December 4, 1957; Raskin, A.H. "Meany Will Drop Teamster Ouster If Hoffa Gets Out." New York Times. December 5, 1957; "Teamsters Await Expulsion Today." New York Times. December 6, 1957; Raskin, A.H. "A.F.L.-C.I.O. Ousts Teamsters Union By Vote of 5 to 1." New York Times. December 7, 1957.

Membership changes continued, albeit at a markedly lower level, throughout the last four decades of the 20th century. On a few occasions, unions in the construction industry disaffiliated and reaffiliated. The most important membership changes, however, occurred in 1968. The United Auto Workers (UAW) disaffiliated from the AFL-CIO on July 1, 1968, after UAW President Walter Reuther and AFL–CIO President George Meany could not come to agreement on a wide range of national public policy issues or on reforms regarding AFL–CIO governance.Lichtenstein, Nelson. The Most Dangerous Man in Detroit: Walter Reuther and the Fate of American Labor. Urbana, Ill.: University of Illinois Press, 1995. A few days after the UAW's disaffiliation, the UAW and the Teamsters formed a new labor federation, the Alliance for Labor Action (ALA).Janson, Donald. "U.A.W. and Teamsters Form Alliance." New York Times. July 24, 1968; Stetson, Damon. "2 Biggest Unions Set Up Alliance." New York Times. May 27, 1969; "Mr. Clean and the Outcast." Time. June 6, 1969. Several smaller AFL–CIO unions either joined the ALA and were expelled from the AFL–CIO for dual unionism or disaffiliated and joined the ALA."Chemical Workers Join Reuther Group." United Press International. September 19, 1968; Stetson, Damon. "A.F.L.-C.I.O. Expels the Chemical Workers for Ties to Reuther." New York Times. October 4, 1969; Stetson, Damon. "Local Union of Retail Workers Is Near Split With Parent Body." New York Times. March 21, 1969; "New Union Is Formed." Associated Press. May 25, 1969. The ALA was not successful, however, and ceased to exist in January 1972.Salpuka, Agis. "U.A.W., in Debt, Halts Funds For Alliance With Teamsters." New York Times. July 6, 1971; Salpuka, Agis. "A Labor Alliance to Be Dissolved." New York Times. January 25, 1972. Over the years, most of the unions which had been expelled or left the AFL–CIO rejoined it. For example, the UAW re-affiliated on July 1, 1981,Peterson, Iver. "After 13 Years, Auto Union Joins A.F.L.-C.I.O. Again." New York Times. July 2, 1981. and the Teamsters did so on October 24, 1987.Noble, Kenneth. "Teamsters Gain A Readmittance to A.F.L.-C.I.O." New York Times. October 25, 1987.

21st century