On 10 February 1927, 174 delegates representing thirty-one states, colonies, or regions and 134 organizations came together at the Palais d’Egmont in Brussels for a Congress on anti-imperialism. Over the course of five days, delegates witnessed and participated in demonstrations of inter-racial and inter-cultural solidarity, heard each other's accounts of colonial oppression, hammered out specific resolutions, and planned for the future. The tone was set on the very first day, when A. Fenner Brockway of Britain's Independent Labour Party joined hands with one of the Chinese delegates, Liao Huanxing, and the two raised their arms together in unity to a roar of applause from the entire Congress. Later the same day Jose Vasconcelos, representing Puerto Rico, reminded participants that imperialism appeared in many forms, and took the United States to task for its “robbery” and “cruelty” in Latin America. He then exhorted delegates to “remember, friends, from all over the world, that Latin America is not only our country but also your country, the country of every man, no matter what race or color, the country of the future and the home of all men.” One of the ten African delegates, Josiah Tshangana Gumede, stood in front of the Congress and told the audience that in South Africa, the country of his forefathers, “we have no place to lay our heads. All the land was taken from us by the Crown of Great Britain and the people were turned away from their ancestral homes which were turned into farms.”

Over the course of the Congress, delegates brought forward twenty-six resolutions and unanimously approved ten. These resolutions spelled out in detail what Congress members stood for, and the future they envisaged. For example, an Anglo-Indian-Chinese resolution committed, among other things, to “fighting side-by-side with national forces for the complete freedom of oppressed countries,” to opposing “all forms of oppression against colonial peoples,” to denouncing “the horrors of imperialism,” and to challenging “imperial politics in order to achieve freedom according to the teachings of class struggle.”

At the end of the Congress, delegates voted to continue their work through the founding of a new organization called the League Against Imperialism and for National Independence. Its purpose was clear: to establish “a permanent worldwide organisation linking up all forces against imperialism and colonial oppression.”