The Unione Sindacale di Base (USB) is an Italian trade union founded in Rome on May 23, 2010. Its ideology revolves around communism and euroscepticism.
The USB was born from the merger of and . With approximately 250,000 members from the founding organizations, it aims to spread across all sectors of the workforce and throughout the country with the goal of building a mass alternative to the confederal unions.
In February 2015, Pierpaolo Leonardi, of the USB National Executive, was appointed Secretary of the World Union of Public Employees, a member of the World Federation of Trade Unions.
The USB has a confederal structure spread across the country, with presence in most regions and provinces. Its internal organization is based on two inter-industry macro-areas: the public and private sectors. At the international level, it is affiliated with the World Federation of Trade Unions.
The union also offers tax and welfare services, dispute resolution and legal services, and has various immigration offices.
AS.I.A. (Associazione Inquilini e Abitanti/ Tenants and Residents Association): association for the right to housing.