Congress of Industrial Organizations (CIO) was an association of labor unions active from 1938 to 1955. In 1955, it merged with the American Federation of Labor (see American Federation of Labor and Congress of Industrial Organizations). Most of the CIO unions had members only in the United States, but a few international unions also had chapters, or locals, in Canada. Most of the CIO unions were industrial unions, rather than craft unions. The CIO organized all workers in a plant into one union rather than just the workers in one particular craft.
The CIO was originally a group called the Committee for Industrial Organization. In 1935, eight presidents of AFL unions formed the CIO to carry on an organizing drive in mass-production industries. The CIO signed up unskilled as well as skilled workers. It placed skilled workers in the industrial unions rather than assigning them to separate crafts unions. Some AFL leaders opposed the idea of industrial unions. But the CIO set up organizing committees and organized industrial unions in steel, automobile, rubber, and other major industries. The AFL did not accept these unions, and expelled unions that had taken part in the CIO. In 1938, the CIO formed its own federation and changed its name to the Congress of Industrial Organizations.
In its 1938 constitution, the CIO stated its main purposes: (1) to organize the unorganized; (2) to improve wages, hours, and working conditions; (3) to establish peaceful labor relations by forming unions strong enough to bargain with large industries; (4) to maintain collective bargaining and wage contracts; and (5) to secure legislation for the welfare of workers.
The Political Action Committee (PAC) of the CIO worked in national politics. State and city industrial councils were active in state and local politics. The CIO supported pro-labor political candidates and legislation in line with its main purposes.
CIO membership grew from about 4 million in 1938 to about 6 million in 1945. In 1949 and 1950, the CIO expelled 11 affiliated unions that it found to be dominated by Communists or by Communist sympathizers.
After many attempts at a merger, the CIO and AFL finally united in 1955. By then, the craft vs. industrial union conflict had become less important. More than half of the AFL’s members were in industrial unions. Rivalry among labor leaders lessened after the deaths in 1952 of William Green, president of the AFL, and Philip Murray, president of the CIO. When the two organizations merged, the CIO had about 5,800,000 members, the AFL about 10,200,000.
