IUSY gained prominence as an international youth non-governmental organization (NGO) with UN ECOSOC consultative status in 1993.
The organization moved its offices to Zurich and published its journal, Youth International, calling for peace (distributed illegally).
[3] After the fascist takeover of Italy, the totalitarian government barred Italian Youth from being a part of the organization.
After the Second World War, the organization formally rebranded to become the International Union of Socialist Youth.
The member countries are grouped into five regions: Africa, the Americas, Asia-Pacific, Europe, and the Middle East.