Oposición Sindical Obrera ("Working Class Union Opposition", abbreviated OSO) was a clandestine

trade union A trade union (British English) or labor union (American English), often simply referred to as a union, is an organization of workers whose purpose is to maintain or improve the conditions of their employment, such as attaining better wages ...

movement in

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

. OSO was originally tied to the

Communist Party of Spain The Communist Party of Spain (; PCE) is a communist party that, since 1986, has been part of the United Left coalition, which is currently part of Sumar. Two of its politicians are Spanish government ministers: Yolanda Díaz (Minister of L ...

(PCE). Many of its members participated in '' vertical union'' elections of 1963 in order to infiltrate the official regime union, including Marcelino Camacho. OSO is considered the precedent for the

Workers' Commissions The Workers' Commissions () since the 1970s has become the largest trade union in Spain. It has more than one million members, and is the most successful union in labor elections, competing with the Unión General de Trabajadores (UGT), which is ...

(CCOO). In the mid 60's the PCE abandoned the OSO in favour of the more successful

CCOO The Workers' Commissions () since the 1970s has become the largest trade union in Spain. It has more than one million members, and is the most successful union in labor elections, competing with the Unión General de Trabajadores (UGT), which is ...

. When the PCE abandoned the organization the PCE (m-l), a 1964

maoist Maoism, officially Mao Zedong Thought, is a variety of Marxism–Leninism that Mao Zedong developed while trying to realize a socialist revolution in the agricultural, pre-industrial society of the Republic of China (1912–1949), Republic o ...

split of the PCE took over the OSO and transformed it in its affiliated union. OSO disappeared in 1977 when it was transformed in the Asociación Obrera Asambleista (AOA).Laiz, Consuelo (1994).
La izquierda radical en España durante la transición a la democracia
'.

Madrid Madrid ( ; ) is the capital and List of largest cities in Spain, most populous municipality of Spain. It has almost 3.5 million inhabitants and a Madrid metropolitan area, metropolitan area population of approximately 7 million. It i ...

Universidad Complutense de Madrid The Complutense University of Madrid (, UCM; ) is a public research university located in Madrid. Founded in Alcalá in 1293 (before relocating to Madrid in 1836), it is one of the oldest operating universities in the world, and one of Spain's ...

. pp. 63–225. .

References

* Wilhelmi Casanova, Gonzalo (2014).
Izquierda revolucionaria y movimientos sociales en la Transición. Madrid, 1975-1982.
'

Universidad Autónoma de Madrid The Autonomous University of Madrid (; UAM), commonly known as la Autónoma, is a Spanish public university located in Madrid, Spain. The university was founded in 1968 by royal decree. UAM is widely respected as one of the most prestigious univ ...

. pp. 29–520. Trade unions in Spain {{Spain-org-stub