The International Workers Aid society, known colloquially by its Russian-language acronym, MOPR,[1] was established in 1922 in response to the directive of the 4th World Congress of the Comintern to appeal to all communist parties "to assist in the creation of organizations to render material and moral aid to all captives of capitalism in prison.

At this gathering it was determined that MOPR should establish sections in all countries, particularly those suffering from the White Terror against the revolutionary movement.

[7] The International Red Aid made its first appearance in Spain as a charity organization during the workers’ revolt of October 1934 in Asturias.

The organization, which included many artists and writers, was later re-formed and expanded in Barcelona in January 1936, with the aim of opposing fascism on multiple fronts.

During the Spanish Civil War, the writer Joaquín Arderíus served as the organization's president before exiling himself to France and then Mexico.

[1] For example, the SRI founded the Escuela Nacional para Niños Anormales (National School for Mentally Disabled Children) in Madrid, with 150 students.

[8] The ranks of the Fifth Regiment (dissolved 21 January 1937), established by the Communist Party of Spain at the outbreak of the Civil War, were also swelled by members of the SRI.

The Fifth Regiment, based on the Soviet Red Army, included Juan Modesto and Enrique Líster amongst its leaders, and fought primarily in the battles in and around Madrid throughout 1936.

[12] Julio Antonio Mella, the Cuban communist leader exiled in Mexico since 1926, was a leading figure in the Mexican section of the organization.