The Congress of Industrial Organizations (CIO) was a federation of unions that organized workers in industrial unions in the United States and Canada from 1935 to 1955. Originally created in 1935 as a committee within the American Federation of Labor (AFL) by John L. Lewis, a leader of the United Mine Workers (UMW), and called the Committee for Industrial Organization. Its name was changed in 1938 when it broke away from the AFL. It focused on organizing 'unskilled' workers, who had been ignored by most of the AFL unions.
The CIO supported Franklin D. Roosevelt and his New Deal coalition, and membership in it was open to African Americans. CIO members voted for Roosevelt overwhelmingly.
Both the CIO and its rival, the AFL, grew rapidly during the Great Depression.