International Molders and Foundry Workers Union of North America

Former trade union of the United States

International Molders and Foundry Workers Union of North America was an affiliated trade union of the AFL–CIO. The union traced its roots back to the formation of the Iron Molders' Union of North America, established in 1859 to represent craftsmen who cast wrought iron metal products. It is now part of the GMP International Union.

In the years prior to the American Civil War existing organization of workers in the iron industry was established on the basis of independent local groups. In 1859, there came a move to forming a national organization in the United States, and the Iron Molders' Union was established at a convention held in Philadelphia on July 5. The first national convention was attended by 35 delegates, representing local iron molders organizations located throughout the Northeast and as far west as St. Louis. William C. Rea of Missouri was elected the first president of the organization and a committee of five headed by William H. Sylvis of Pennsylvania was appointed to prepare a declaration to the iron workers of America. Initial dues were set by the organization at $10 per local with an additional $10 per delegate sent to the national convention. This proved insufficient and in 1860 per capita dues were initiated at the rate of 5 cents per member per year. The organization grew rapidly during the years of the Civil War, with non union journeymen joining in great numbers. By 1866, the Iron Molders' Union touted 137 locals with a total membership of just under 10,000.

A series of mergers led the union to change its name to the International Molders and Allied Workers Union. In 1988, the Molders and Allied Workers merged with the Glass, Pottery, Plastics and Allied Workers International Union (GPPA) to create the Glass, Molders, Pottery, Plastics and Allied Workers International Union (GMP).