Along with other unions like the Unión Sindical Obrera (USO) and the UGT, it called a general strike in 1976, and carried out protests against the conditions in the country.

Taking as reference the clandestine union Oposición Sindical Obrera (OSO) the first workers' commissions were organized during 1960 in Asturies, Catalonia, Madrid and the Basque provinces of Gipuzkoa and Bizkaia as labor disputes emerged outside the Francoist national-syndical movement.

The first "comisiones" were boosted by the Communist Party of Spain (PCE), Christian labor movements (JOC and HOAC [es]) and other groups opposed to the Spanish State.

For many historians, one of the first places where the Workers' Commissions were formed was the valley of Laciana (province of León), within the Minero Siderurgica de Ponferrada (MSP) industry.

This finally took place on 20 (day that coincided with the assassination of Prime Minister Luis Carrero Blanco, which led to the suspension of the trial for a few hours), 21 and 22 December 1973.

The murder of 5 labor lawyers in 1977 (members of the union and the PCE) in Madrid that year was followed by a massive funeral, more than 250,000 people participated, and the strikes that followed helped the legalization of the organization.

In May 1977 CCOO suffered another split, this time from supporters of the maoist Workers' Revolutionary Organisation (ORT), that formed the Sindicato Unitario.

Especially massive and historic was the 1988 Spanish general strike, organized jointly with the UGT, which had a 95% of following, and forced the government to totally withdraw the Youth Employment Plan.

[8] In 2002 CCOO and UGT called for a general strike against a decree of the government of José María Aznar that made firings cheaper, eliminated agricultural subsidies and encouraged job insecurity, known as the decretazo.

CCOO held its IX Confederal Congress in December 2008, with 1.2 million members and 120,000 elected delegates in the workplaces of Spain at the time.

At the Ninth Congress Ignacio Fernández Toxo was elected general secretary, surpassing by 28 votes José María Fidalgo.

On September 29, 2010, the CCOO called a general strike to protest the José Luis Rodríguez Zapatero government's plans to raise the retirement age and cut spending.