Leopold II, King of the Belgians, founded the Congo Free State in 1885 after almost ten years of political preparations in Europe and explorations in Central Africa. Swiss bourgeoisie took part in the creation of the then-to-be Belgian colony by the participation of national geographical societies in the International African Association (founded in 1876). Although Swiss partnership to Leopold II’s project pretended to help the fight against slavery, quite different were actually the reasons for the Swiss bourgeoisie to support the Belgian King financially, legally and intellectually. This article analyses the origins and the challenges of colonial philanthropy applied by Swiss geographical societies during Congo’s Leopoldian colonization.